here are the facts-

i'm building a phil/deep v wheelset (3x rear, 2x front). i usually weigh between 110 to 120 lbs. the wheels will see mostly smooth, even, paved asphalt, with the occasional patch of gravel, and maybe a pothole or two. given the circumstances, i'm wondering if i really need the 32s. your thoughts/opinions?

oh, and one last thing- world class is now offering phils with low friction bearings. what's the consensus on these?

Assuming the price and availability of the hubs is the same, I don't think there would be much of an advantage running 28 with that setup. You are sacrificing durability for weight savings on a wheel with hubs and rims that are pretty heavy by themselves. I think the weight/aero advantage of a low spoke build is really only worth it in a 'race only' wheel situation.
I'd say the same with the bearings. The seals in a low friction bearing are worse at keeping out the elements, sand, grit, etc, and really only provide benefit in race situations that only occur in good weather, i.e. the track. The amount of extra drag a well sealed bearing is nothing compaired to the rolling resistance added by patches of gravel and mud.

i'm riding 28h phils to deep v's, 2x front 3x rear. i weigh 140 lbs, they ride strong. they were built at freewheel in sf and i had them built at travis' suggestion after he saidtold me they frequently build the same setup for messengers who haven't had any problems.

I wiegh about 100lbs more than you and ride on 32h hubs with no prob. I say if you want 28's, go for it. You'll be fine.

I'm 145lbs and I think my combination will be phil/deep-v 32 holes, 3x rear, radial front. I think that should hold up well to anything I would throw at them.