You need to do your research! This is a site I suggest reading through to help determine what you need.
Most important is to sort out what you need.
As for Mac. I agree with less to worry about and the power of Unix. Apple has a great e-mail application called "Mail". The nice feature about Mail is the program is powerful at managing Spam. I used to get tons of spam, I used to be a Outlook advocate! Switching to Mail, the "Training Mode" was run for 2 weeks. Till this day 100% of my spam is filtered and i have not once had it mistaken a friends/clients e-mail for spam. A real time saver.
When I shopped around for a PC and Mac laptop - Mac was able to offer me more software such as Microsoft Office X included with the purchase of my iBook. Don't get caught up in the Mhz myth. The G4 has a shorter pipeline than the P3 and P4 will ever hope to have... (well until the Itanium hits the public market in bigger numbers.)
Generally speaking - today Macs and PCs are really close in how they perform for users. Mybusiness has both Mac and PC. Both get the job done hands down. I will always be a Machead, but open to whatever gets the job done.
Best of luck to you!
(Loving my G5 dual 1.8 running OS X Panther on 2 Gigs of SDRAM.)