I purchased the original set of Eneloops (white) from my local Costco about a year ago, and I have not had to buy AA, AAA, C Batteries, or D Batteries since. The set came with these very cool 'spacer' shells that transform simple AA batteries into C & D size batteries so you could use them on most portable electronics (not to mention all the kids toys and video game remotes).
Sanyo has also released a higher capacity XX (Black and Grey) Eneloop battery rated at 2500mah, which holds a charge capacity of 75% up to one year in storage. This is not a replacement for the original version. The new XX battery should charge on the original Sanyo Eneloop charger, but if used with the optional 'boost' charger, a single battery can be brought to full charge in about 40 minutes. I honestly don't know anyone using the new XX version, and the (white) original ones I'm using seem to do perfectly fine.
Besides the Eneloops's slow drain abilities during storage, these batteries will power any of your devices up to 5x longer than just standard alkaline. Definitely worth it in the field, and will save you money over time. I've used them with the AA battery adapter on DSLR Battery Grips, LED Video Lights, Portable Audio recorders, Flash Triggers, Canon Speedlights, to Wireless Microphones. It's an investment up front to get started with Eneloops, but i've been rocking all of my batteries for more than a year in constant rotation on the charger, and these have to be the best rechargeable batteries i've ever owned.
I've been using the Zoom H1 and Tascam DR-08 as 'body packs' instead of using a Wireless setup. I'm still using the old Audio Technica ATR-3350 Lavalier Microphone setup, and I have to say that i'm quite happy with the workflow. You just can't beat this combination for the price and speed in getting things setup. For more demanding audio, of course I have a different set of tools. In my book, I found a clear winner as far as the type of work this combination is being used for, and it's the Zoom H1. Why? Leaving it at the highest bitrate for basic short audio capture provides you under 1 hour on a 2GB microSD card and they both work great. You can drop down the audio bitrate and grab yourself more time, but what if you really need even more? Well I just shot a few events in which this setup was used, so to be safe we needed to go with the 8GB MicroSD Cards that I showed in this post: http://cheesycam.com/canon-60d-shipping-actually-shipped/. BTW, they've been working flawlessy and such a good price for those microSD Cards.
Unfortunately, possibly a Tascam Firmware issue, the Tascam DR-08 could not see the 8GB microSD card. Only the Zoom H1 was able to see and utilize the full 8GB providing 4 times more recording time. You never know how long it's going to take for an event to get started, or how long until it's over, so I just felt safer with the unit that can house the larger microSD card. Here's another tip that's a bit related. Regular batteries don't stand a fair chance with today's electronics. I hear many people complaining about how fast a battery grip with AA's, LED lights, or an Audio Recorder can run down batteries very quickly. I push the Eneloop batteries not only because they are rechargeable, but because they DO hold 4 times more capacity than a regular battery. If you want to use your Zoom H1 as a body pack, give it a fighting chance and put some quality batteries in.
This is what my charging area looks like the night before a shoot. Tomorrow i'm just helping out with a Wedding, so I gotta get my charge on. In these images you'll see my aftermarket 5D Mark II (or 7D) batteries, and my Eneloops. It's going to be a light day, so i'm just bringing one camera out 5D Mark II, 24-70mm F/2.8, 100mm Macro IS, 50mm F/1.4, two 580 EX II flashes, and Radio Popper PX's.
It's quite a hassle to keep track of charged and uncharged batteries if you're relying on the power to get you through your next Project. I’ve been using these Sanyo Eneloops for years, and they are by far the best Rechargeable batteries i've ever used. Normally rechargeable batteries aren't recommended in certain devices, and if left for just a short period of time, they lose power. Sure you can wait 4-8 hours recharging them to use them again, but in a few weeks (without using them) they will still lose power.
The Sanyo Eneloops are designed to be a different type of rechargeable and can even maintain up to 90% of their charge if sitting for up to 1 Year!. I've never tried that claim, but i've never had a problem with dead batteries either. They can run a bit high in retail stores, but Amazon and B&H both have some of the cheapest prices for these Eneloops.