The August issue of CustomPC featured a review of 35 different cards. None of them counted as perfect in their view, as many were overpriced for what they offered, and the only high-end cards offering DirectX 10 support were the GeForce 8800GT series.

Gamespot performed a similar evaluation, choosing only the higher-performing models.

If you're not worried about using a current-issue, DX9 based card, and aren't looking to play at resolutions higher than 1280x1024, the Radeon X1950 would be your best bet. 512MB should be fine, as that's what's recommended for Portal.

Smart Dalek, that isn't for portal, that's by a website called "half life portal." Thats recommended for running Half Life 2. This does lead me to believe it should be fine for portal, however IIRC Half Life 2: Episode One recommended higher settings than HL2, so the same might be said for Portal.

I can't seem to find any recommended settings for any of The Orange Box games that are coming out, and this worries me somewhat.

Portal's based on the Source Engine. It's also set in the HL universe.

Though HL2 and Episode One had the same recommended settings, the HDR effects of Episode One were pretty demanding on some systems who ran HL2 perfectly fine. Portal seems to have a lot of effects like depth of field and motion blur, and I can't help but think that these will affect how smoothly the game runs in the same way HDR does.

I got an X1950, and I'm just duckily happy with it. And I have no problems getting good framerates at resolutions higher than 1280x1024 (1680x1050 is my monitor's native resolution). I was thinking of upgrading for Hellgate: London, but my enthusiasm for that game lessens with every passing day, so I think this'll be my card for quite awhile...