I switched to a MAC notebook about 15 months ago mainly because I did not like the other machine our company offered. Like you I was a PC user for years, and if a IBM THinkpad (Lenovo) had been available I would of have acquired this. First the good points, The display is great and the machine is stable. Now for the but, being a IBM user I did not find the switch easy. The way I was thinking did not translate into the way I needed to think to use a Mac. Also, using Office on a Mac works well but does not have all the features that the windows version does. ALso, I do not use Vista in my windows environment only XP Pro. I have run into some things that only work on Internet explorer and not on Safari or Firefox. Also, for email you could use Entourage from Microsoft if you use Microsoft office. For free things you could use Thunderbird for email, and open office instead of MS office.
In summary the Mac is nice but I would have been better served with a Windows machine, since this is what I know. When running XP/Pro and the software you mentioned this is very stable and easy to use. It is also the least expensive solution. If given a choice I would get a Thinkpad with XP/PRO as well as office.