Don't go for the 05/06 gsxr's... worst of the bunch.
GSXR's are a good bet. Plenty of parts... plenty of them for sale.. and they are the cheapest/most comfortable stock.
Having said that - any bike can be modified to personal taste. Go sit on all of them first.
If you are expecting Ninja 300 fuel mileage on a SS bike.. you're in for a surprise. You can keep it under 3000 rpm and still get ~220 kms a tank (~$22 to fill up). Especially if you get an aftermarket exhaust. Driving normally, my old (03) GSXR got 220 kms before the light came on, bone stock. Changed to a Yoshi slip on.. I was lucky if I got 185 kms.
www.fuelly.com