R.I.P. - GeForce 4 Ti4000 series

I really like what I've seen and heard about the 4200, and I'm worried that
the price is going to start spiking as the things become scarcer. But I
don't want to buy if it's going to be hopelessly obsolete -- or if the price
of the newer cards (say the 5600 Ultra) is set to start dropping
precipitously.

The Ti4200 still outperforms new entry level cards (Radeon 9200 or
FX5200), and performs similarly to the newer midrange cards (Radeon 9600
or FX5600) until you enable AA and AF or run heavy pixel shaders like in
3DMark03. It's got enough raw horsepower that it will probably handle
newer games just fine as long as you tone down the eye candy.

I'm happy with my Ti4200, but if I were buying a new video card today,
I'd probably spring for an FX5700 Ultra or Radeon 9600 Pro, because
they'd be more future proof. Even still, when you can get a Ti4200 for
half as much, and get 80% of the performance in current games, it's hard
to pass up the GF4.

What are the odds that it'll be compatible with a new(ish)
motherboard 12 months from now?

It won't be any less compatible than a Radeon 9800 Pro or any other
modern 1.5v AGP card (i.e., anything newer than the Voodoo3).

I know PCI Express is up and coming, but I imagine new PCI Express
motherboards will still include an AGP slot for a few years anyway, so
compatibility is probably nothing to worry about.