Something I'm just discovering is that with the update to 1.2.4, Optifine no longer works for me. It's fine with Frontier/Sanctuary at 1.1... Some of the textures are a tad wonky without the HD support.
*edit* This might fix the issue, it's updated for 1.2.4
http://www.minecraftforum.net/topic/...hd-fix-234-02/