One way around the slow encoding speed of LAME (slow when comparing LAME --alt-preset standard to almost any other encoder) is to do your encoding as a seperate step.

IE: Rip several CDs to WAV and then encode the CDs while you do something worth while like sleep.

I've been doing it this way as I find the most labour intensive part is the ripping and ensuring the Album/Artist/Track/Genre/Year info is correct, but this is also the least time intensive, while the encoding requires zero labour but lots of CPU.
That way the 30 minutes encoding time become irrelevent.

Oh, for the record I'm using AudioGrabber & LAME APS