The one thing on my must have list I haven't seen mentioned is backup. I use Memeo's LifeAgent. It'll work non-apple storage devices and it backs up your files as they change (vs. Time Machine which does time-based backups.) My mac's HD went bad on me just last week and I also killed 5 or 6 notebooks before I went mac with its blessed magnetic power chord attachment. Trust me in saying nothing beats a backup

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I have VMWare and find it bloatly and horribly slow and never use it anymore -- its not worth the headache. Just to open it takes ages and it'd suck up most of my notebook's RAM. Most of the time I use wine, or specifically CodeWeaver's CrossOver which is still wine but a lot more painless. CrossOver has Adobe Photoshop, IE, Excel, Lotus Noes, EndNote, MS Office, Outlook, Powerpoint, Visio, Quickbooks, etc in its 'supported' list that pops up when you install new Windows software so in theory they work. Might be worth giving it a test while you are trying VMWare and Parallels.
Another advantage of the wine route is everything is stored directly onto your system vs. inside an image as with VMWare. So you can easily drag and drop files around, save it from or attach to email, etc.