I agonised over upgrading the wheels on my Kestrel for weeks... after much deliberation and a lot of spreadsheet comparison I decided it wasn't worth the upgrade.
Of course the irony was just after I decided I didn't need new wheels I had an incident and then needed new wheels (along with a few other things). I went for Aluminium wheels as a bit of a compromise over performance, weight and durability becasue I didn't want to have to change my wheels for everyday riding.
I picked a set of SRAM S30 AL Race wheels after a pretty good deal from the bike shop. The downside it took almost three weeks for them to turn up and to be fitted so they haven't had much of a ride but they do look good.
Their big test will come this weekend with the Brisbane to Ipswich Challenge... I'm sure there will be a post review after