Let me tell you about my gear...
My recording gear includes an Edirol R-4 and an Edirol R-44 as well as an iRiver H140.
More recently, I acquired some of the Olympus line of PCM Recorders like the LS-10, LS-11, LS-3, LS-7 and LS-100,
which I almost exclusively use with external microphones, my main recorder being the Olympus LS-100 at the moment.
For microphones I mainly use a mid-side stereo system which includes a Sennheiser MKH80 as the side and a Sennheiser
MKH40 or a Sennheiser MKH20 as the mid microphone.
Currently I use the MKH80/40 combination with the LS-100.
For the other Olympus recorders I use plug-in power microphones like the 
Telinga Clip-On's by Klas Strandberg.
They have very low self noise and perform perfectly even in harsh environments.
After experiencing that rodents do love to chew on microphone cables, I found that Primo EM-172 capsules can easily be built into a camouflage Pelican case, so that I now have several of those. They enable me to make very good quality unattended recordings of up to 50 hours in any weather conditions in a rodent-, bear-, and people-safe way. Recordings with this setup will soon be up on the website.
For under water recordings I use a pair of Aquarian Audio H2a-XLR.
I also own an Audio Technica AT3032 stereo pair as well as two Technica AT3031, that I rarely use. Additionally I have a pair of AKG 480 with CK 62 omni capsules which I do not use for Nature Recording any more as they don’t work well in humid environments.
Finally I have some Soundman OKM in the Classic, A/V and Rock version, that I used in combination with Minidisc and DAT recorders at the very beginning of my nature recording days. They are now off duty.
For preamps I use a Sounddevices MP-2 and most recently a LAKE PEOPLE C360 (which I very much recommend).