RAM, Mhz.... actually, the slowest Mac on the store is faster than any Dell... they provide 2 or 3 models of each just for the maniac of details.

the only detail really is the RAM... the more apps you want to run at the same time will make your decision... i actually have 1.5Gigs on my Mac Pro, and this is not needed to add more in my situation. 800Mbs are reserved for the webserver and the rest for my apps... Photoshop is always running on 75% of the RAM i have so i do not have to calculate that detail.

you can now decide if you go for a tower or a iMac... the Towers are flexible for hard-drives, video cards, network extensions... but aside of that, they are the same as the iMac...

remember that you do not have drivers on a Mac... even if you buy a PC printer or keyboard... you do not need to configure and seek the specs of your extensions to see if they work on a Mac... just lately, i bought a new keyboard (baby dropped my coffee in my old one), and i bought the cheapest Microsoft keyboard (8$... yep... 8$) and in the specs it was noted to not work on a Mac... the only detail not working was the Alt key switched with the Control key,.... so yes, even Microsoft makes Mac keyboard!.. lol

if you are not into gaming, that's less questions... everybody know that Mac have less games, but when you have Windows installed in your bootcamp you can run PC games like in the most powerful PC... you just need a little extra RAM!

i'm not a Mac fan only... you see, i can tell you that you can run everything PC into a Mac... the detail is that a PC ...CAN'T run Mac apps... even if you have something virtual, the shelled Mac emulators are 25% efficient... for the PC/Windows fans or the guys in need of both technologies, the only solution is a new Mac..

oh, btw, when i talk about no need to upgrade when you buy a Mac... it was not about a self-upgradable Mac, but a comparaison with most of the PC sellers that will provide you with free upgrades to make it work with Vista... on a Mac, even with the new OS released in 4 months, no need to tweak your computer to make it work... OS-X Leopard works on a Summer 2001 iMac... (ok, it is slower, but it works! - no tweak)