I had a Logitech mouse and keyboard combo... they worked fine and were comfortable but the Set Point software sucks so much ass! I had to manually close it in order to be able to use middle mouse and the forward/back thumb buttons in games! With Set Point open, they did not respond no matter what options I modified.
I just bought myself a CoolMaster Sentinel Z3RO-G and it is fracking awesome!! I can't recommend it enough. On the fly DPI adjustment from 800 to 5600 (or any custom amount) and up to 6 profiles for different games. Program it with macros and multi-button keypresses, and it has 128kb internal memory so once programmed, it will always remember! Also has a neat light and OLED screen
All that, and it costs only $50. I honestly think this mouse is too good for the price. You should check it out.
Also, I got the Microsoft Sidewinder X6 keyboard to replace my wireless Logitech stuff, and it's really good as well with lots of macro buttons.