Many thanks to all who responded, for all the info and links.
My needs are modest - simple home video editing from an analog camcorder. Most of what I really want to do is get rid of sections such as forgetting to turn the camcorder off and getting a few minutes of shoes, mud etc :)
I've been digging around for a couple of weeks now - the Hauppage and also the Pinnacle (Miro) PCTV tv tuner cards seem to be well supported and work well (well enough for my non-pro needs anyway).
For digitising, the Pinnacle DC10plus is a mid-range board that seems to have a good rep for analog digitising and writing out.
The ATI All-In-Wonder range apparently do not have any VIVO (video-in video-out) support under linux, often freeze X and under the supplied windows drivers are pretty flaky as well. Just too cheap'n'cheerful to be useful I think - tempting, yes, but not if it is going to be constant frustration - I've been there too often before.
I am planning to build up a new PC fairly soon for linux and W98se use with the intention of moving in stages to all-linux. I am at the 'thinking what to buy' window-shopping stage and have made most decisions.
For graphics I shall probably use a cheap generic TNT graphics card. I am not a gamer so don't need lots of high-quality 3D power and compared to what I'm using at present the TNT should be a good upgrade. Xfree support is said to be rock-solid.
I shall avoid the All-in Wonder cards for all of the above reasons plus the upgrading flexibility gained by separating functions between different cards.
For the digitising etc I think I will probably try one of the cheap TV tuner cards as that may do all that I want - if not then I will look again at the extra money for the DC10plus.
If anyone *does* know someone who is using a DC10plus, even under windows, I would really like to get in touch as I want to check some of the functionality in the version sold in the UK. Specifically if it will accept SECAM input ( I watch a lot of French TV using a french sat dish, tuner and tv). If not then I will have to consider sourcing one from France.
Regards Syd