Get the 802.11G. It's only marginally more expensive. Even if you don't need it today, you will grow into it.
It's better for more than just moving flac/shn files around on the LAN. If you have a shared printer on one machine in your house, you can spool to the printer faster. Access to search shared networked drives is faster. If you export the UI from a remote machine, that will be faster. Pretty much anything that you do between machines will enjoy a performance improvement. It also gives some much needed headroom if you are streaming media on your lan. Streaming video will eat 802.11B bandwidth but with the higher rate, you can do other things with less potential to affect the performance of media stream. I'm playing with that application now for work.
Even though you have just one machine, you may want people bring over a laptop to swap shows over your wireless lan. The G will be faster. Of course, if the one bringing the laptop is some hotty, maybe you would prefer the longer transfer times.