which dbz saga is the best

This depends. If you separate the Saiyan and Frieza sagas then:
1) Freeza
2) Vegeta
3) Buu
4) Cell

If you combine the Saiyan and Frieza saga (like I feel it should be) then:
1) Saiyan-Frieza
2) Buu
3) Cell

COME NOT BETWEEN THE DRAGON AND HIS WRATH

1. namek
2. raditz
3. cell
4. tienshinhan
5. fusion

I like all the sagas but my favorite part of dragonball is from the beginning right up until planet namek explodes. The android saga which leads right into the cell saga is very good aswell. Cell is also a great and interesting character. The whole boo saga comes in last for me. But I do like the way the series ends. Another thing is I really like any parts in dragonball when there is a tournament going on.

no love for the namek saga?

The whole Ginyu saga, some of the best fights of the series for me. And everyone kept topping everyone else in terms of power.

After that it's the Android saga for all the SSJ goodness.

"Ain't found a way to kill me yet,
Eyes burn with stinging sweat."
ALICE IN CHAINS

The Frieza saga was the only good story in the whole Z series... The rest is redundant crap.

Saiyan Saga to Cell Games Saga are the best sagas in DBZ

I agree with smb3264, matt-cricket, celloprof, Philip_90, Firedragon524, and gunnar_zero-1 on their previous takes on this matter.

The Namek/Frieza saga is the ultimate saga and the best thing about Dragon Ball in general. This is the best story-line out of all the Dragon Ball series. It features the majority of the Namek Saga, incorporating the three-way guerrilla warfare between Vegeta, the Earthlings, and Lord Frieza and his minions. This is the pinnacle of the series at its height and no Dragon Ball story is complete without this explosive saga. The original manga titles are "The World's Greatest Team," "The Lord of Worlds," "Earth vs. The Saiyans," "Goku vs. Vegeta," "Dragon Ball in Space," "Battlefield Namek", "The Ginyu Force", "Goku vs. Ginyu", "The Wrath of Freeza", "Goku vs. Freeza", and "The Super Saiyan." I would have to say that if it were not for these specific chapters, I would not even be a Dragon Ball fan.

Battlefield Namek is my absolute favorite as it features the journey to Namek, the arrival on Namek, and the betrayal of Vegeta as he blatantly goes against Lord Frieza. This is the most impacting to me of all Dragon Ball history as it features the fights between Vegeta against Zarbon and Dodoria, Frieza's top two elite henchmen and Generals. The slaughtering of the Namekian children and elders at the hands of Zarbon and Dodoria followed by Dodoria's chase of Gohan and Krillin and his eventual revelation of the truth behind the destruction of Planet Vegeta to the demonic reptilian transformation of handsome warrior Zarbon, followed by the arrival of the Mercenary Squadron of the Ginyu Tokusentai (Jeice, Burter, Recoome, Guldo, and Captain Ginyu) who are all felled by Goku & Vegeta, and the wild chase for the Dragon Balls make this the most compelling collection of Dragon Ball manga to ever be released and the original Japanese anime version is equally as good as it features the best soundtrack by Shunsuke Kikuchi, specifically the tracks "Kyoufu no Ginyu Tokusentai" and "Tenka Wakeme no Chou-Kessen" being the pinnacle of musical synchronization with perfect matching of every nerve and every physical combat maneuveer. Zarbon's beat-down of Vegeta is by far my favorite fight sequence in all Dragon Ball. Zarbon and Dodoria are not only the best supporting antagonists in Dragon Ball for me, but they happen to be my favorite characters in the history of all anime.

Additionally, for the other sagas in the Dragon Ball franchise, if we are to include Dragon Ball and GT with DBZ along with their saga breakdowns, this is how I would order them along with the best thing about them:

1. Namek Saga [Zarbon, Dodoria, and Cui] > Ginyu Saga [Jeice, Burter, Recoome, Guldo, Captain Ginyu]> Saiyan Saga [Nappa, Raditz] > Frieza Saga [Frieza]
2. General Blue Saga [General Blue] > Red Ribbon Army Saga [General White, Captain Yellow, Colonel Silver, Major Metallitron, Sergeant-Major Purple Ninja Murasaki] > Commander Red Saga [Staff Officer Black, Commander Red, Mercenary Tao]
3. Androids Saga [Android 19, Dr. Gero] > Trunks Saga [King Cold]
4. Babidi Saga [Pui Pui, Yakon, Dabura, Spopovich, Yamu, Babidi] > Majin Buu Saga [Van Zant, Smitty, Evil Buu]
5. King Piccolo Saga [Drum, Tambourine, Cymbal] > Fortuneteller Baba Saga [Invisible Man, Mummy Man, Dracula Man, Devil Man] > TienShinHan Saga > Tournament Saga > Piccolo Jr. Saga > The Saga of Goku
6. Garlic Junior Saga [Spice, Vinegar, Mustard, Salt, Garlic Junior]
7. Dragon Ball GT Super 17 Saga > Black Star Dragon Ball Saga [Ledgic, Don Kee] > Shadow Dragon Saga [Eis, Haze, Rage, Oceanus, Omega] > Baby Saga
8. Kid Buu Saga > Great Saiyaman Saga > Fusion Saga
9. Imperfect Cell Saga > Perfect Cell Saga > Cell Games Saga

And if we look at the short variation of specifying sagas, then it's in this order:

1. Frieza
2. Dragon Ball
3. Buu
4. DBGT
5. Cell

I would also put all the DB movies above the Cell Saga. The pinnacle of the series and the height of the emotion and the actual story-line connecting to the major plot ends after the Frieza Saga. Vegeta's betrayal and his struggle to outwit Frieza as well as all the things he goes through make this saga amazing. His take-down sequences against Zarbon, Dodoria, Cui, Jeice, Burter, Recoome, Guldo, and Nappa make this whole journey worthwhile. Another amazing aspect was Piccolo's sacrifice for Gohan. All of it came into place with perfect writing and the portrayal of Piccolo and Vegeta as the main story-line driven character development aspects of the story were the most powerfully compelling. Aside from this, all the villains were important plot devices in the primary story, setting the story into motion by causing the destruction of the Saiyan race. My favorites in the entire story are Zarbon and Dodoria; for their performance, brutality, and sinister behavior being repaid in full with brilliant death scenes. I am strongly in fond of henchmen characters as they always do the dirty work onscreen and this is highly appealing for the visual aspect.

The true ending of the manga is when Trunks slices Freeza into pieces and executes King Cold. Toriyama was to stop there and reveal that there will always be Super Saiyans in the future to halt evil. But fans wanted more so he continued with the whole Terminator and Majin thing. After the Frieza Saga, it is barely even about the Dragon Balls and the desire to collect them. I would say that the appearance of Android 19 and Dr. Gero was also well portrayed along with their pivotal roles as plot devices.

However, directly after the appearance of Android 17 and Android 18, the series gets bad and is in limbo for a long time until we pick up again directly after the over-long and boring Gohan and Cell scuffle. The Cell Saga was a heavy step in the wrong direction and the worst of all the sagas to me; particularly and specifically the very poor ending of the Cell Games. It does pick up again after this with the Babidi Saga being a positive one, but the series suffers again with the childish fusions of Gotenks and Vegito and silly fighting candy junk in the Fusion Saga. So basically, the Frieza saga has no weak points and it is the pinnacle of the series along with having a menagerie of the best villains I have ever seen in anime history.