128 should be fine. I run an identical setup at home on 128MB Xen server, and by far the biggest memory hog is mysql. Here's the memory footprint, 12 days since the last reboot:

dan@flint:~$ free total used free shared buffers cached
Mem: 131252 110836 20416 0 4632 38480
-/+ buffers/cache: 67724 63528
Swap: 131064 2228 128836

Those are pretty healthy numbers -- just enough swapping to indicate that it doesn't have more memory than it needs, without being significant.

Yikes, looks like you're discarding newlines. Okay, look in the chat game on mcios.

Whoops, had forgotten there would be instances where white-space would be significant. Hmm, looks like I need a PRE-tag handler.

But thanks for that info - as you (probably) know this thing hangs off a mysql database and although I've tried to minimise the number of queries needed to display any particular page, when it comes down to it you've still got to through a few Mb of tables around.

s/through/throw/. Another thing I want to add is a "whoops" feature that lets you correct typos in your previous move.