The new 600 is getting a ton of great feedback, and it's super affordable for a high-dpi gaming mouse. Me personally, every time I pump up the DPI (even on shooters), as soon as I turn it down again I play better, so try to worry less about dpi and more about balance and dpi-adjusting mice, because shooters/MMOs do practically require it.
http://www.newegg.com/Product/Product.aspx?Item=N82E16826104914
My personal favorite is the Mionix Naos now, however, simply for ergonomic grip and so much comfort. It houses all of your fingers and lays a little flatter than a Razer mouse, whose curve is pretty crazy after you stop using one. It has 8200 DPI (more than enough) and has DPI adjustment buttons, but only has two extra buttons. Since I use a Logitech gamepad and play few MMOs, it's perfect for me, as it feels just right in my palm. Does take getting used to though.
http://mionix.net/products/naos-8200/