I own the Axim X30 high (624MHz w/ WiFi) and am very pleased with it. Unfortunately it was discontinued a year ago, replaced by the X50 line, and subsequentially the X51 line. The X51 (Click here for the Cnet Editor's review) has the same functionality as the X30, but also packs the latest version of Windows Mobile (now 5.0), finally includes a PowerPoint viewer (The X30 lacked that feature), touts updated versions of Pocket Word and Pocket Excel, supports presistent memory (you won't lose your data if the battery dies), and has more ROM for storage. Thus, if you fell in love with the X30, you may want to turn your affection to the X51. (The X30 can now only be found on Ebay and the like, though usually at excellent bargains.) You can click here to compare all three X51 models. The X51v (high-end model) is currently $499, though Dell very frequently places it on sale for $399. Otherwise the X51 mid should suit you quite well, as it includes WiFi and the latest software, on sale for $319.

However, there is one problem with your expectations. The built-in microphones are designed for taking voice memos, and more recently, basic voice commands using specialized software. Their quality is simply not good enough to capture a lecture or meeting in the quality you would expect from a stand-alone voice recorder. You can purchase a PDA to meet your other needs and try it out for yourself, but I am confident you'll turn to carrying a voice recorder opposite the PocketPC.

If you have any other questions, feel free to ask.

Hope this helps,
John