I would say that the worst basic failure on the N900 has been in getting an adequate twitter client. Twimgo is the first to achieve saved searches, I heat. I just installed the latest version. It has been saying "loadng tweets" for the last ten minutes or so, with no other signs of action. An earlier version worked well for me for a time.

Witter worked well but never achieved saved searches, then went belly up.

No others achieved much, if you ask me.The web-only Tweetgo is cool but takes too long to start up.