I've just found that RealplayerSP is a great replacement for Quicktime when rtsp playback is required - it's more efficient and has extra options and features. Playback in general is on a level with VLC. I'm using it here on my iBook (Tiger) for Youtube - Omniweb, with a Nokia mobile user agent loaded, bypasses Flash playback and serves up .3gp files, which open automatically in Realplayer. As you can see, CPU useage is super low so it's great for low end systems. RealplayerSP can be downloaded here: http://www.techspot.com/downloads/4088-realplayer-for-mac-os-x.html EDIT: No longer working - broken by Google.