get the smaller fahgettibout it -- one of the best u-locks on the market.
yes, you cannot put it in your back pocket easily, who cares? it fits just fine under your belt.
and, like I said before, I regularly use the fah u-lock through rear wheel, seat tube, and bike rack. works great. parking meters are a bit too thick...and if thats the case, I just sheldon brown it.
my front wheel has a road hub, so I use locking skewers on the front. I also bb/superglue my seatpost and saddle.
For extra security locking, I have a armored cable and a on-guard mini u-lock. I use the on-guard through the fah u-lock to fill in the extra space.