I like the Bad Yard Club and Perfecto mixes of ‘Lemon’, and Ferry Corsten did an awesome trance remix of New Years Day a few years ago.
A newie I like is the 7" Jacknife Lee version of ‘Vertigo’.
Also, the version of ‘If You Wear That Velvet Dress Bono’ did with Jools Holland is spectacular (not really a remix, but what the hey!)
I'm not a big fan of remixes in general though, and most of U2's sound really dated.
I can't sit through Melon, and the remix-o-rama that was the b-sides disc from best of 90-00 was pretty poor.
A bit of a tangent:
I've never understood why U2 packed that disc full of remixes when there are plenty of quality actual b-sides that they didn't use from that era, i.e. ‘Satellite Of Love’ and ‘Two Shots of Happy, One Shot of Sad’ (among others).
Cheers,
Andrew