If you want something cheap to go fast on, '99 GSXR750SRAD or the Y or K1. I had a '98 Blade for 9 years (Ti Akra, Maxton front and rear, etc) and it never felt as good as my SRAD, i would take anyone on with that thing, and regularly did, and almost always came out on top. Its a 4 stroke 2 stroke, great fun.
But you have already got a decent bike in the Fazer, so I'd go for something different. Since I started riding sportsbikes 30 odd years ago that's all I had, but with the anti-speed attitude nowadays I have had to turn away from bikes that are only good at one thing i.e. going very fast. That's why I bought a Fazer (capable of going very fast, but nice to ride when you are only going at 5/10ths), but I also have a VN800, very good little bikes, relatively cheap, and a different kind of enjoyment from riding it around, nice to bugger around with too, and there are so many of them, second hand goodies are quite cheap. You don't have to dress it up like a tarts boudoir, teach yourself to paint and take all the bits off you don't want, and you'll have something individual to you. The best thing is that you can transform it into something different quite cheaply every winter if you want to. The good bit is, you will always get your money back on your investment.
The bubble has got to burst with 80's/90's Strokers pretty soon, the prices are ridiculous and they can be real money pits.
R1's are very good sportsbikes, but not that different from a Fazer with some mods and a decent rider on board.
Supermotos are great around town and on country lanes, but the TDR250 I had in '96 had to go, I was a real menace to other road users on it, I just couldn't help myself, it was only fun when you pushed it hard, over roundabouts on the back wheel, through bus stops, using drop kerbs as ramps, baiting ANY other riders on anything, it had to go, I was safer on something that would do 170mph!