Honestly here is what I would do...
Mavic 517's on XT hubs, should be under $200 US
Specialized Fatboy 100psi slicks, 1.5" $30ea?
11-25 105 cassette $25-40?
(so you get bigger gears and less of a gap between gears)
If you get the 517s off of Pricepoint, Performance, Jenson, Nashbar, they are really cheap. Sure, they aren't handbuilt, but if you take them to a shop and have the dish/true/tension checked for about $12 per wheel you can save a lot of coin. This is one point where its hard to make an argument for buying handbuilt wheels from your LBS, unless you are a very demanding rider with very particular tastes.