Getting the BEST POSSIBLE QUALITY for DIVX/XVID

[Ashrack]

I just put together a rig for my father mainly for DIVX/XVID playback and some games, Word, VIDEO EDITING...
Sempron 2600+, 1024MB RAM, 80GB 7200HDD, RADEON 8500 64MB TV-OUT. GIGABYTE NFORCE3 MOBO.
This computer is connected to TV. So we can watch DIVX/XVID movies.
I usually install FFSHOW 20050803(with all settings to default) and AC3FILTER.
What I would like to achieve: How can I get the best possible DIVX/XVID quality for playback. Perhaps a different codec, or I have to tweak some settings??

[anonymez]

for mpeg-4, i recommend post-processing full preset (but that depends on the initial quality), mplayer, accurate debocking.

for blur & NR, denoise3d, luma 0, chroma 0, time 5. HQ ON.

i also adjust brightness/contrast/saturation with picture properties

there is not much more that can be done

[UncasMS]

best settings for what: creation or playback of your files?

[Ashrack]

Yes, for playback.
Changed the original message so that it is clearer what I want

[Ashrack]

So the best quality is gained by using FFDSHOW and to tweak some settings?
I don't need other codecs?

[UncasMS]

no, you dont

ffdshow has been my most favourite playback filter for years
it's quality is excellent