i have some castelli aero race bibs and they're awesome. can occasionally be found for close to $100.

i've also heard a bunch of people (everyone over at slowtwitch basically) rave about the desoto 400 mile bibs. they're currently on sale for $123 at sportsbasement.com, and there's a 20% coupon on top of that (snow20) and free shipping, so that puts you at around $98. but i've never used them personally.

but yeah, rollers (or a trainer) will never be as comfortable as riding outside because you can't move around as much, so do keep that in mind. i don't think there are any bibs that will let you sit on rollers for 2-3 hours at a time without moving and still be comfortable.