What are you guys using for lav mics on external recorders?

I use an Olympus ME-15. Works great.

i am using an azden lapel with a sennheiser clip. these seem to work well and are inexpensive.

Amazon.com: azden lapel microphone clip ex503

this isn't the exact clip but very close

Amazon.com: Ezprogear Ez6308t8 Lavalier (Lapel) Microphone Clip (6.2mm): Musical Instruments

I 2nd the ME-15. I started a thread in the 'all audio' forum about possibly upgrading to a 'Rode Videomic' retail cost $280. A well respected individual replied to the thread with a test video of examples.

For web-distribution, you want to max out your levels at -3db, and most computer speakers are so crappy the ME-15 is fully capable of delivering a good sound.

If, however, you are planning on distributing on DVD or theater than you want a better mic since most surround systems have 1000X better speakers than computers.