Just some brief observations:
1) I didn't think i would need a wireless mouse -- now i wouldn't go back to a wired one, the wire does become annoying and an obstacle. Only downside is need to change or recharge batteries. Read reviews to make sure you don't end up with a mouse needing an inconvenient recharge every 10 minutes. I had a rechargable one once that had to be put in its "base" to recharge, which i just could not ever remember to do. Never had any trouble with reception of my wireless mice.
2) Wireless keyboard - can't see the use for this if you dont work from bed/couch/etc and constantly move keyboard. However, given quality of wireless mouse transmission i can't see any reason why the wireless keyboards would have any noticable defficiencies over wired versions.
3) i've had bad experience mixing microsoft and logitech mice recently, and so i would probably go with either both MS keyboard+mouse or both logitech keyboard and mouse. Ive used mice and keyboards from both companies and been very happy.
4) i'm currently using the
MS ergonomic 4000 keyboard and have grown very fond of it, even though i never expected to like one of the ergonomic types. Be warned though that it may be hard to switch back and forth between ergonomic and non-ergonomic keyboards if you use one type at work and another at home, etc.
5) in short my summary recommendation: buy a Microsoft or Logitech bundle which includes a wireless mouse and a wired or wireless keyboard depending on your preference.