Haven't read the whole thread but these are my opinions.
Gaming mouse have a massive advantage if you play fps, precision, speed, tracking and smoothness are a massive gain in games like this, if you play mmo then not so much.
wireless mice used to have input lag noticeable in fps, not so sure about todays though id wager youd have to spend a decent amount to get a wireless mouse that is adequate, again mmos etc not so much an issue.
wireless keyboards dont suffer any of these issues, they are just the same as there wired variants, that or a wired mouse with such speed and precision has done a very good job of compensating for any issues that may have been there.
Gaming keyboards, they look pretty.... usually, some have macros options and or lcd displays but essentially the keyboard function is the same, tactile preference may have you lean either way to a favorite but but for fps ive never noticed a gain when i moved from my dell keyboard to a razor tarantula, mmos would benefit form the macros keys on gaming keyboards i suppose but that all down tot he user and if they would take advantage of that feature.
This being said i opted for a third option, i got my self a belkin n52te speed pad, i use arrow keys instead of wasd and got sick of pulling my keyboard backwards and forewords across my desk, this pad is much smaller and fits my needs perfectly, im downgrading my keyboard to a mini keyboard with no num pad or center keys between so my decision comes down to orientation and space alone, i plan to upgrade to the logitech version soon just because i like the look of it.
So in conclusion, you may notice gains from a gaming mouse but a keyboard not so much, get what you feel fits your desk best, can afford at the time and like the feel of, no other gains really unless you are in need of macros and that being said you can get a gaming mouse form razor with plenty on now.