Um don't buy a Buell. They are maintainence nightmares, the ONLY saving grace was the great support from Buell.
HD dropped them like a bad habit. IMO it's very clear that they aren't planning on supporting the brand. Yes, they are required to uphold the warranty and provide service for a limited time, but I bet the days of really cheap Buell parts are over.
Not to mention they have absolutely NOTHING to compete with a 600 supersport. The 1125 really isn't even close.
I do agree with angry hampster in that the 1125 (or any twin) is more usable than the inline 600's. What makes you specifically want one? IMO they are annoying on the street, get a 750 instead (although they are a lot more expensive since dealers are less likely to haggle)
Out of the 600 supersports I would get the CBR600RR w/ abs. The gsxr-600 isn't a bad bike but you really have to wind the motor out, and nothing about the latest ones are 'special'.. They're just plain jane 600 supersports. At least the CBR is topping the magazine tests and (I believe) has significantly more midrange. Also buying new, the Honda will hold its resale value.
Don't get me wrong, I love Suzuki - I've had an SV650, TL1000, GS500's, and more. It's just that specifically the GSX-R 600 doesn't have anything going for it above the competition. The R6 is a better track bike, the ZX6R makes more power, the CBR is a better 'all around' bike.