That hardware should handle anything you throw at it ATI drivers
are a bit of a problem though but that shouldn't prevent the basic
install.

See you got 11.10 working on a separate HD - not multi-boot then, just
change the boot drive when you want to switch OS ?

Apache is only needed if you are serving up web pages from your system
so are you doing that ? If so, is this just locally or over internet ?
Serving web pages over internet brings a whole bunch of issues around
security and really you would be better with the server edition of
Ubuntu and reading up on how to lock it down. Doing it with a desktop
version is possible but you do lay yourself wide open if you aren't
careful - yes Ubuntu is secure on the desktop but servers are a whole
different ball game and you really do need to know what you are doing.
If nothing else, serve from a dedicated machine and have it on a DMZ
through the router to isolate from your network.