personally, i have about the same download speed as you do, so i set mine as a T1.

a t1 = 1.5Mb/s
mine is 3Mb/s and yours is really close to that. so its double a T1, so the T1 setting should work perfectly fine.
however, my upload speed is 768Kb/s which is equal to 0.75MB/s... yours is 0.50MB/s

yea i think setting it as a t1 should be just fine. it would maximise your upload/download bandwidth to its full potential. (you will see more sources being swarmed from.)