A former Mac user, I have been involved in an illicit Windows dalliance for the last 7 years. A wholly unsatisfying relationship, my time with Microsoft came to a close March 2008 when I got this 15" MacBook Pro Core 2 duo. It's a nice machine and OSX leopard is about as different from Windows as Sampson was from Delilah (conniving wench).
There is definately a premium to pay for the latest Mac hardware and software. However, since the bug-plagued release of Microsoft's Vista, there's quite a premium on new PC boxes loaded with the old XP. At least my premium is on new gear.
I use Aperture 2.0 to manage my images (I shoot an average 100 RAW keepers every whale watching day) and to do basic tasks such as RAW conversions, cropping and level adjustments. I have experience with Google's comparable and free software "Picasa", which is excellent for a free program but only avail for Windows. I recommend it. I also have experience with some other professional level image management software but Aperture takes the cake with a full feature set, stability and integration with Adobe Photoshop. The learning curve is manageable but takes some commitment, unlike Picasa which is far more automated, though feature poor. However you should be ready to go from moment 1.
I use Adobe Photoshop CS3 Extended for more advanced photo-editing and what can I say that hasn't been said? Previous to CS3 Extended the last version I used was 6.0, about 6 versions ago and I used it professionally (print layout -- newspaper mostly) for 6 years without need to upgrade. Digital photography is punk rock dude, let's face it.