Yea FIOS looks great, but im in dallas, and they have it in the 14 suburbs around dallas...but not actually IN dallas. So i think im going to go with roadrunner 10mb(bit)ps package, which seems fast enough. What are you doing? if you mean fast surfing, you definately dont need t1 and up, (from what i heard t3 is just like two t1 lines combined so same dl speed just can supply 2x comptuers) but if your doing serious downloading ie movies and such then you might want to get around 5+ mbps connection.
To find your dl speed, devide the mbps number by 8. IE 10mbps is 10/8 = kbs so you would have 1.25mb(byte)per second