As a recent switcher (though I have used Macs for years and years - I've always had PCs as my primary home computer), this has been the only area I've been kind of disappointed with OS X/Mac, like at all. Apple Mail is better than Entourage in Office '04 (which is just too old to be useful for more than just Excel stuff, because Numbers '08 sucks if you are trying to enter in long/complicated strings), but I still don't love it. Plus, because I was using Outlook '07 before switching, my PST files won't open using the old Outlook 2001 converter, which effectively locks me out of all my data - and I have multiple PST files that are over 500 megabytes. I mean, I essentially have every piece of e-mail from August 2000 to two weeks ago in those files, the pre-August 2000 mailboxes got lost when I accidentally backed up the wrong directory after a particularly heinous Windows ME experience (worst. operating. system. ever.) -- but I haven't found a way to natively access them on the mac.
Thus, I am just using Parallels and Outlook '07 as my primary mail client. VMWare would work too (or Boot Camp - though that doesn't really work for a integrated option, meaning, you want to be in OS X but actually check your mail) - and so far, this is working out pretty well. I hope that Office '08 will have PST support (if it is Universal Binary, there is no reason it shouldn't) and that the mail client will be along the lines of Outlook '07 so I can just have everything in house. Definitely try out Fusion or Parallels (or both) -- I've been super-impressed with Parallels (though I'm not using the latest beta -- just 4060 or whatever the last official update is) but have heard great things about Fusion too.
Best of luck! A lot of things do, "just work" (I was pretty psyched that my 3 year old HP All-in-One was immediately recognized as soon as I plugged it in -- including the OCR support -- and I was able to avoid the 200 megs of BS HP software that Windows always requires me to load), but there are some things you'll need to fiddle with. However, since you are a coder - it shouldn't be that difficult a transition.