The magic vs mighty mouse debate is two-sided for me, (and I've found apple mice most comfortable for me btw, as I only use apple mice and tablets).
PROS:
Magic Mouse
-wireless
-no scroll ball makes for easier scrolling
-momentum scrolling
-very tiny, great for travel(though you will be getting iMac)
Mighty Mouse
-can come in wired or wireless
-traditional scroll ball
-middle click
-all four buttons("left click","middle click", "right click", "squeeze" can be customized to be anything, though I set the traditional buttons for LMB, MMB, and RMB, and use squeeze for expose, but it can be anything. I also find that squeeze works better on the wireless version over the wired, but that may have just been my luck).
CONS:
Magic Mouse
-momentum scrolling tends to be very sensitive to scrolling in apps where scrolling activates something (very annoying in Final Cut, After Effects, and Nuke for me personally, but PERFECT when I need it in Safari, Pages, Finder, ect. Scrolling can be turned off via sys prefs, but is sometimes a minor annoyance to do so
-REQUIRES BATTERIES
-no native Middle Mouse Button, and 3rd party software don't really emulate it nicely IMO
Mighty Mouse
-the wired cable is short, though isn't a problem running from an iMac or the side USB port on the wired keyboard
-the mouse ball will every few months POSSIBLY clutter with a little dirt, possibly making it hard to scroll. The fix though is to unplug mouse, put upside down, and roll mouse ball on a sheet of paper for about 10 seconds. It wasn't THAT big an issue for me back in the day
-squeeze may be a bit more sensitive on the wired version, though that may have been my mouse in particular
Keyboards, keyboards, keyboards
Wired vs Wired Compact vs Wireless
wireless is nice due to lack of wires(duh), but requires two batteries. It also does not have a number pad, which isn't a problem for me. I also use it as a media control when my MBP is plugged into my tv, but again you seem to be using this for work, so it may not be a necessity
wired vs wired compact
the wired is great because it does not require batteries and has two usb ports on the side. You have a choice between compact, and regular which includes the numpad. Since I don't use the numpad like ever and like simple keyboards (basic keys I use), I prefer the compact. however, the extended is better if you need to use the keyboard on top of your lap or something, as it is easier to balance.
Well, those are my 2 cents, so good luck