The other option is ATI, I don't actually own any ATI cards and have only tried using them with non-free drivers in the past to get them to work with non-free software which wasn't very successfult, so you will probably want to research the validity of my answer.
With ATI cards you also get a choice of a non-free driver which supports all the features of the cards or a free driver that supports 90% of the features of the cards or The free driver that supports 3d hardware accelerations which is a good thing. These cards also have support for TV-Out, unfortunatly I don't know anything about the radeon range and support with Linux so I would research this yourself although I would think that any ATI Radeon 9xxx card would probably fill your requirements quite well. At lest this should give you a pointer to things to google with.
I have an ATI Radeon 9600 pro(got it a few weeks ago for £120~) and its a very nice OpenGL card. For 3D (in Linux that basically means OpenGL) performance ATI is better and cheaper, though I've only ever seen windows benchmark results(www.tomshardware.com). If you want open source drivers for a top of the range ATI card(9700 or 9800) or a mid range card(9500 or 9600) then you are out of luck. However there are some drivers are available from ATI's website that are closed source but work with all of there new cards. If you really want open source drivers then the dri.sourceforge.net site have drivers for the ATI Radeon cards up to the 9200 model.
This site has a good roundup of the ATI Radeon drivers for linux: http://homepage.hispeed.ch/rscheidegger/atilinux_oct03/ati_linux_comp_oct03....
Ive also had a NVidia GeForce 2 MX card(had this until a few weeks ago) which has a TV-out port but is quite slow on most newer games(like Unreal Tournament 2003) but can play Quake 3 and older games quite well. There is however no open source drivers that support OpenGL for any of the NVidia cards.
Some good site that i know of for getting gfx cards are: www.ebuyer.com and www.overclockers.co.uk.
- Dennis Dryden