I also considered buying a gaming mouse with a bunch of buttons on it, but would this be considered kind of cheap? Would hardcore gamers scoff at the idea of having a bunch of actions tied to mouse buttons?
It's not about scoffing. If you want nice macros, Logitech's software for the G-series keyboards (and G400 mouse) is awesome, though you'd need to learn a little programming. Most of the time, once you're used to a KB and mouse, you'll only want macros for little things, like if a game only does toggle for crouch, but you want a hold crouch. It's that outside of MMORPGs, where players making macros are typically expected by the game devs, and where any careful movement doesn't matter, too many buttons makes things more difficult. Tilt wheels can be bad, too, making it hard to get a middle click. You want a mouse that is comfortable, and tracks well.
An MX518 is a perfectly fine mouse. If it's comfortable to use in Windows, it's fine for games. Oh, but if tracking speed control seems to be a problem,
check this out. Forced mouse acceleration was one of the piss poor regressions introduced in Vista that survived into 7.
There's just no need to add mouse buttons for what the keyboard is there for. With practice, you won't have to think so much about pressing shift to walk, ctrl or c for crouching, etc.. If more common setups cause you to falsely press things, or make it difficult to add more held keys at once, you can change them as you need to. Once you're used to using the keyboard in general, new mappings will not take long to get used to.
I think Logitech's G13 is excellent, and the software, while it has a learning curve, is the best out there. The high wrist bend on the N52 ruins it for me (I tired it once, and it started hurting within a couple minutes), though I think it has superior keys and layout, and it's basically impossible to use all the keys of the G13.
My keyboard is an IBM Model M. If I needed to buy a gaming keyboard today, it would be the same layout (PC-101/PC-104), with Cherry MX black or brown switches. No macros, no LEDs, no "ergonomic" split, etc..
My number one need is good wrist support.
Staples, Walmart, Best Buy, Office Depot, etc., should have those on the shelf.