The Sony ICD-PX720 costs about $50, records in decent quality to its built-in 1GB flash memory, has a USB port to transfer files to a PC, and runs for 35 hours on two AA cells.
The bad news is that you have to use the included Sony Digital Voice Editor software to translate the Sony-proprietary format to MP3. It won't translate directly to WAV format.
The Olympus DS-40 costs about $95, records in WMA format to 512MB of built-in flash memory, has a USB port, works with PC or Mac, and runs for 30 hours on two AA cells. You'd have to convert WMA to WAV in a separate step.
The Tascam DR-07 costs about $140, records in WAV format to SD card (2GB card included), and has a decent preamp (much better than the Sony or Olympus models listed above) and built-in stereo mic. You can transfer files to PC or Mac via USB, or by removing the SD card. There's a $20 rebate offered by Tascam on this model.
You could get a good deal from one of Tascam's resellers because the DR-07 has been replaced in Tascam's line by a newer model, the DR-08. The DR-08 is considerably more expensive because it was just introduced.
Flintstone