Personally, I love my Mionix 3200. Being new to gaming mice, you'll probably like pretty much any quality mice you buy, so decide if you're picky about buttons/size/weight/lpointless lighting/ergonomics first. If you don't care about any of that, I recommend one of the Mionix Naos mice for one simple reason: their ergonomics are awesome. Many people who get them say they are the most comfortable mice they've ever used. And their sensors are good, too. The cooler master spawn mouse has a similar but shorter ergonomic shape and is cheaper as well, but I hear less rave reviews.
On the other hand, if you're not right-handed, or lift your mouse off your mousepad often, the Naos 3200 isn't that great. The Naos 5000 has an adjustable lift distance though. Everyone has different tastes, so perhaps you'd prefer a mouse with a giant freaking hump that feels like a mountain pressing into the palm of your hand. Logitech it is! At least some of their models, I've only had a few. I think most people adopt their grip to the first mouse they like rather than the other way around, but it sounds like you already have a starting point with no small mice, so that's useful.
As for sensors, you pretty much have four big choices: quality optical, quality laser, ****ty optical or ****ty laser. When it comes to quality laser mice you pretty much want an Avago 9500 sensor or one of the Razer Lasers (phillips sensor: no minor problems with acceleration but not as sensitive or touchy as the 9500 - personally I don't like the touchiness of the super-sensitive laser mice - it sometimes shifts a pixel when I didn't intend it to move). For quality optical sensors, you'll want an Avago 3090, 3060, or one of the exclusive Razer optical sensors (Avago 3X88). How to tell what mouse has what sensor? Mouse Reference Thread in the stickies of this sub-forum. ****ty optical sensors include the Pixart sensors (minor hardware bug that can't be fixed by software) - I haven't heard many good things about non 9500 or Razer Laser mice, so I can't call any of those out.
Too open-ended for you? Anything that has a quality sensor listed above and gets ok reviews should do fine. Get a Naos 3200, download the driver, set the polling rate to 1000Mhz, turn off acceleration, set the DPI sensitivity to 1600, and enjoy. But anyone on this forum can (and will) recommend their favorite mouse without much explanation
. Oh, if you're looking to stay around $50 you can rule out most of the quality laser options.
As for mousepads: for optical mice it doesn't matter all that much. I get pretty good performance on basically any surface. My old mousepad was wearing out after like 12 years of use, now I'm using my desktop, lol. Laser mice are trickier (and more sensitive to textured surfaces). If you get a Laser mouse, make sure to get a mouse pad, and especially for the Avago 9500 sensors, make sure to get a mouse pad with a hard (NOT cloth) surface. Pick your favorite company or e-sports sponsor and grab whatever hard pad they offer if you go laser.
The g500 is one of the Avago 9500 sensor mice, and not the best reviewed for the reasons a few have already stated. On the other hand, if it meets your under $50 requirement, it's one of the cheaper implementations of that sensor, and some people like the atrocrious shape of logitech mice. The Xai mentioned above is another Avago 9500 mouse if you want to consider that as well. Make sure to budget for a hard top mouse pad for it though.
Look around to see how to set your mouse settings (for instance, windows mouse speed set to 6/11 to avoid software interference, in-game settings for a game like SC2 set to 51% speed/sensitivity. Then try out the various DPI whatever mouse you get can do. For instance, when I got my Naos 3200, I tried 800 for about a day before I was sure it was too slow for me. Then I tried 3200 for a week trying to get used to playing at a high speed. Then I decided that was too fast to be accurate, and I've been happy with 1600 DPI ever since. Optical mice have limited settings, whereas most laser mice can fine-tune DPI. But as you are new to gaming mice, fast/medium/slow options should be enough to get in the right ballpark for you, and you'll simply learn to use that setting, so fine-tuning won't really be needed.Edited by MisterFred - 1/11/12 at 1:48pm