I just got a Edirol R09HR, and I was wondering if I could get a Mic recommendation, I will be doing some shows, but for now mostly quiet nature recordings.
For quiet nature recordings, the most important specs for the recorder are its noise level at various gain settings. For mics it's their self noise and sensitivity specs. Stealth recording of concerts have other requirement -- let's discuss that later.
How do you get low noise in a recorder? If you had a professional budget, you should buy a truly pro recorder with pro-quality pre-amps and A/D converters. If you don't have the pro budget, you have no choice but to buy one of the low-cost digital recorders.
None of the low-cost recorders (like the Edirol R09HR, M-Audio MicroTrack II, Marantz PMD-620, Zoom H2, Sony PCM-D50, Tascam DR-1, Olympus LS-10, Fostex FR2-LE) approach the professional recorders (Sound Devices 722, Zaxcom Deva, Sonosax SX-R4) for low noise specs. In my opinion, the way to get pro level noise performance with the low cost recorders is to use an external mic pre/ADC. The only low-cost recorders that allows an external mic pre/ADC are the M-Audio MicroTrack II and the Sony -D50, We recommend the MTII -- much less expensive. By itself, it has noise performance comparable to the Edirol, but it's lower cost (currently $235). Add a good mic pre/ADC to the MicroTrack (or other recorders with digital audio inputs) and the recorder becomes a "bit bucket", not influencing the sound in any way. The mic pre/ADC controls the sound quality and noise level. For mic pre/ADCs, you might have a look at our Mic2496 V2 and the Grace Lunatec V3. Either of those brings the performance of a low-cost recorder into the pro range. There are others, but not many that are portable.
How do you get low noise in a mic? For condensor mics in general, the larger the diaphragm, the lower the noise: a mic with a 1-inch diaphragm will have lower noise than a 1/4" mic. If you don't need a miniature mic for portability or stealth, concentrate on the larger mics. Choose a pair that has low noise and high sensitivity. Rode makes a bunch of mics that are known for low noise, reasonably sensitivity and are good values. If price is no object in your search for sound quality, have a look at the world class mics from DPA, Neumann, AKG, Schoeps and a few others. (We're DPA dealers and can offer good prices on those.)
If you need miniature mics for portability and stealth, in my opinion, there's no mic that has the combination of fine sound, excellent sensitivity and the lowest noise in its class than the DPA 4060. We use a tightly matched pair of them in our High End Binaural (HEB) mic set. It's not inexpensive (around $900 to $1000, depending on configuration) but in my opinion there's nothing else that approaches them. Combined with a low-noise recorder, they're as good as it gets for the combination of sound quality, low noise and portability. They'll work fine with your R09HR. (We have lower cost solutions too.)
If you're doing things like recording bird calls, you might consider a parabolic mic, like the folks at Telinga offer.
I will likely get one of the Church Audio Pre-amps down the road, but for now I am looking at a powered mic like the AT822 or Rhodes NT4.
You might know this, but it's a common misconception so it's worth repeating -- "powered" doesn't mean that the mic has a built in mic pre-amp. It only means that it doesn't require external phantom power to operate. Also, in my opinion, the AT-822 (and the -825) is not in the same class as the Rode NT4, not for sound quality and not for build quality.