I'm fairly proficient with Windows, and recently bought myself a MBP.
I use Entourage for my company mail on my Mac, and copied (exported) all my Outlook mail folders and address book to my MBP with ease. I also access my company network remotely by VPN and Citrix which was simple to setup. My company doesn't permit any personal machines on the network in the office.
I use Mac's "Mail" for my private email.
The minor problems I've still goto overcome is Safari does not remember the zoom used for each web site, which makes me stick with FF.
Another thing, Adblock only works if you set Safari to open in 32 bit mode which isn't a problem for me.
I am also dissapointed that all the add-ons I use on Thunderbird aren't available for the Mac version.
This thread was the first time I'd heard about not having a right click - the MBP track pad with gestures has the two finger tap or click for "right click" in addition to other track pad functions that are way superior to any others I know. I'm not that impressed with the Magic Mouse - I use the track pad and mouse about the same amount these days.
CS4 is waaaaaaay faster and better to work with.
Dashboard is great - I've captured the FX insert from a web site and use that in dashboard , really smart (the Mac that is).
Overall, I'm sticking with the Mac.