I thoroughly recommend getting surround speakers for this game - its absolutely superb!!! You really get the feeling in youre in the middle of unrelenting mayhem & chaos - everytime a grenade goes off it rumbles through you, and AT-STs/AT-AT is just ground shakingly good.
Plus you get explosions and laser blasts fomr the back speakers "surrounding" you - and you can annoy your downstairs neighbours by turning the subwoofer up to 6...
I got really excited at the prospect of Dolby Surround, Lucas Arts, and THX (their invention for heaven's sake) and was disappointed. The sound is crisp and clean, explosions rock, but there's no go use of 5 point surround. I should be hearing chatter behind me, distant explosions, etc ... the best time I noticed the effect was when I was running down a long tunnel and I heard something chasing behind me - but this was isolated. Other games use 5 point sound very well so should Star Wars.