Well if you just want to boot into x, most likely all you need to do is change the driver in your XF86Config to "nv" instead of "nvidia".
Then unistall the old NVIDIA_* pakages.
Go to the nvidia site and get the .18 pakages. Reinstall those.
The you can change back the driver to "nvidia"
That should do it.
As for upgrading the kernel... of course upgrade when you need to. But just be prepared for what your are doing. If you've modified the kernel, dont expect those modules to remain in there afer upgrading.
Yes it is a pain in some ways, but I have had many pains in windows also.
And I wont even get to what it was like before packages were here. Imagine downloading the sources, compiling object files, linking to kernel config, recompiling kernel, installing new kernel etc. That's what it was like not so long ago.
Personally I find up2date and packages amazing. I just installed Linux for the fist time in about 3-4 years. I use to have a few linux boxes and alot of Suns and SGIs. I was extremely surprised on how easy it has become.