I agree that Macs seem expensive, but if you compare a Mac Pro or MacBook part-for-part to its PC counterpart, you'll find that the Mac is often cheaper than the equivalent from Dell or other major PC manufacturers. The problem is that Apple doesn't drop their prices as the models age, so a Mac Pro costs the same today that it did 12 months ago. At that point in its life cycle, it is more expensive than an equivalent PC. That's why the best time to buy is when Apple launches updated hardware.
Psystar (or your own hackintosh) could be a viable option. I've never used one myself, but I've looked into them. The biggest benefit is the ability to upgrade your hardware. Mac Pros provide a certain level of upgradability, but the video card options have always been limited. If you're a hardcore gamer or constant tweaker, PCs are still the best choice. When I switched, I decided I was spending too much time and money tweaking and upgrading. I used to build all my PCs from scratch, so that was a tough adjustment. In the end, I just wanted to get my work done and not worry so much any more about my machine's internals.
My transition was pretty smooth. The biggest money hit for me was replacing my PC software with the Mac equivalents. I bought Office 2004 for Mac and upgraded from Adobe CS1 to CS2, and thankfully Adobe has a platform switch program that lets you change your software license from PC to Mac and vice versa at no charge. Mac Office lagged behind the Windows version for a long time, but with the release of Office 2008, they're now pretty much equal in terms of features. Now that I'm full-on Mac, I find that there are plenty of Mac-only options that are just as good--and often better--than their PC equivalents. I used to be a HomeSite/Dreamweaver user, but now I use an app called Coda for all my web dev work, and it's a Mac-only product.
Being in web development, I have a few remaining applications that require Windows (SQL Server, Management Studio, IIS, etc.), so I use VMWare Fusion running XP for those. Great product.
Switching is a bit of a process, and I did get frustrated at times because OS X is different from Windows, but once I deprogrammed myself, I really started enjoying my Mac. I'm on my second tower now (started with a Power Mac G5, and now have an Intel-based Mac Pro). I'm happy for now and don't see the need for a major upgrade for another year or two. I already have 10 gigs of RAM, but I need more hard drive space, which is an easy upgrade (Mac Pros have cable-free hard drive bays, pretty damn sweet), and I might upgrade the video card (currently have an ATI X1900, best available for the Mac Pro at the moment is an 8800GT).
Overall, moving to Mac has been a great experience for me.