I use Azureus 2.5(?) and I agree with everyone that it uses too much memory. The sad thing is that Azurues began as an open source project and as with everyone else, I also dislike the path it's heading for, such as becoming Vuze or Azureus 3 and going for commercialization.
The ideology for GPL licences is that it is open source, but not necessarily free... but on the other hand, open sourced software can be dissected and reverse-engineered and be rewritten and re-released as another GPL license and maybe "BE free."
I think everyone has heard of Linksys' WRT54G series routers, I believe the first routers to use the Linux kernel, making it open source, but not necessarily free.
Anyways, when Azurues is fully commercialized, it's time to switch to another client...