"The laptop memory is the same as PC laptops use, the Desktop memory is the same as PC desktops use"
No kidding? Apple.com memory is 2x store memory. 512MB is $150.
Go to: http://www.macseek.com/ and check the prices for yourself.
Current desktops take PC3200 or PC3200 DDR, depending on the model. Laptops take PC2700 DDR or PC 2100 DDR, depending on the model.
512 MB of laptop memory is $78 in either flavor. Sounds like about 1/2 of $150 to me.
Check out ramseeker.com for buying memory.
My 2 cents on your dilemma would be to go to the Apple Store with a list of what your wife wants to use her computer for and what she needs to be able to do. Talk to one of the staff there and make sure all your concerns are addressed.
Macs play nicely with PC's now and even though I have Virtual PC on my Mac, I rarely open it. If you do get VPC, make sure you have virus software for it. I know of a person who got a virus on theirs, but the Mac OS was fine.
Be careful to realize you might be having to deal with a very happy wife if you get a Mac for her. She will fall in love with it.
Cheers! CC :)
P.S. Make sure you get an AirPort network going - it rocks!