Wano - I sort of have the same predicament over choosing to blow a wad of cash on a new PowerMac setup to replace my aging AGP/Gigabit PM 400 - or purchase a nice DV camera (I want the Panasonic AG-DVX100).
I have decided to go with the PowerMac for a few reasons:
1. I'm in film school and have access to DV cameras
2. I can always rent DV cams
3. I can use the PowerMac to *make* money through freelance design projects
4. Useful for school, etc.
Now, at the same time, I'm looking for a consumer grade DV cam to purchase - not to use exclusively, but more for location scouting, practice/run-throughs, experimentation and recreation.
...true the cameras depreciate a lot slower than PCs do...if you have a big, important project to do - you could consider getting the camera, shoot everything you could possibly need - sell it and THEN get a Mac.
But for me...and I'm not sure where you live, but if you have access to cameras through schools, rental shops or even PBS affiliates - then those are always there for you. Access to a computer maybe a different story for you (or is it?)
And again - if you're a straight up camera/cinematographer than you'll need the camera. But if you have projects which you'll be doing the post for...I say throw the big guns into post.
But that's just me, my needs and my opinions - I thought maybe it would help with your decision....good luck.
kb.