My setup:
P4 1.8 ghz w/ Asus P4T Bios
256 mb SRam
ATI AIW 8500 Radeon Video
Soundblaster Audigy Sound Card
I've tried VDub, Ulead VS 7 & 8, Ulead DMF 2 & 3,
Pinnacle 9 and MMC 9 and get the same audio / video synch problem.
So, I think it could've been some kind of hardware/system setup problem.
So I recently updated my ATI & sound card drivers to the latest versions and still get the same audio synch problems - is there something else i should check?

SHould i just re-install win XP and all software again?

Two things:
1. The ATI MMC software will by far give you the best experience for capturing. It takes advantage of the software and hardware on the card. The other programs you listed will only use their own software. Ulead and Pinnacle Studio software are well-known for sync errors.
2. The "Audigy" model of soundcards is known to cause delays on video capture. Something about the cards must delay the audio processing or have a much longer journey than normal cards. This is why I use SoundBlaster non-Audigy cards and then Turtle Beach cards.

Maybe, MAYBE, reinstalling Windows will help, but no promises. You may also want to be sure you've got good drivers for the Audigy cards.

Some of the AUDIGY issues are documented on the ATI.com site in a few places.

one of the first things i did was to update to the most recent audigy drivers.
So the Turtle Beach that's availble now with DSP/5.1 support could work better? At only $59, it would be cheaper than spending a couple of days refreshing my machine.

When I upgraded to Windows XP last month, my old favorite, the SoundBlaster 5.1 card I'd had for years and years... would not work. The XP drivers would not work, something I think to do with my motherboard (Intel/RDRAM) and XP. Not really sure. After playing for a day, I gave up. I bought a Turtle Beach Santa Cruz for about $50 and I was up and running in minutes.

I personally think the Creative drivers are too old and not cared for enough. Turtle Beach won my support after this last incident.

Add that to known issues with Audigy cards, and I think it may be time to change. I gave my old SB to a family member, they got a free sound upgrade from me.

I would say this: with a good return policy, you've got nothing to lose by trying out a new card for a few days.

Bought the santa cruz and installed it. this is my first non-creative product in years. Where i stand now is that i'm able to hear the video and it looks like it's synching, but when i play it back, there's no audio. So i'm sure i've set something up wrong, but Turtle Beach's support forum is awful compared to ati or creatives - i can't even dl the latest drivers... any ideas as to the problem?
the cables seem to be connected correctly - i don't think i could hear the video onscreen if it wasn't? The line-in mute button is not checked....

Also noticed that the volume was significantly reduced throughout the system (even though the slider bar on the volume control was at max volume) - do i just have a crappy card or what?
You mention that you didn't like the 16-bit sb 5.1 card - i was just going to check that one out - did it also have synching problem?

I do notice the decibel range (volume) of the Turtle Beach is not as loud, but it's not often I pump up my sound to 100% anyway. It was only very slight, at least on mine.

I'd say you don't have MMC setup correctly. Either that, or it corrupted, and it's time to remove all and reinstall all ATI drivers/software.

I wire mine internally along the AUX channels.

I re-installed the ATI drivers and MMC - i am able to capture via Vdub - into AVI, with sound and went through with Tmpgenc and authored the dvd and the sound synched
- but haven't been able to get sound from ATI MMC - either capturing as Mpeg or AVI.
Also - how do you wire internally along the AUX channels?

On the ATI card, and on any decent soundcard (like the ones we're using), there are AUX channels (as well as other internal connections) on both cards. Look on the bottom of the card, on the side farthest from the motherboard. You'll see the inputs there.

Get the 3-pin white connector wire (should have come in box with either or both cards, but may need to be bought at a computer store) and connect the two points. Electronics stores like BEST BUY and COMPUSA will NOT have these. You need a computer parts store like FRY'S or MICROCENTER or some other computer knick-knack shop. Again, it should NORMALLY be in the box with the card. This is different that the 4-pin slim one used for the CD players in/out digital audio connectors (from soundcard to CD/DVD-ROM).

Setup ATI MMC in the Initialization Wizard to use the AUX as the input for sound.

Under the WINDOWS sound (speaker icon in system tray by clock, or under CONTROL PANELS and SOUND) be sure your AUX is not on mute, and in the OPTIONS->PROPERTIES->RECORDING area, that AUX is checked and has decent volume (not too high, not too low).

If you need any visuals, let me know, but that should be fairly easy to find just reading the words I put down.