My family is running low on regular batteries, and with MKWii coming out tomorrow, I know those batteries won't last through the day. Do you guys have any recommendations as to what brand of rechargeable I should persuade my dad to get?

Get regular rechargeable batteries at your local best buy or radioshack.

i use duracell rechargeables. they've paid for themselves ten-fold because of how much i play. i know i would have gone through at least 200-300 batteries by now if i didn't have those rechargeables. tell him it will save $100's.

Go for duracell! or one of those chargers for $20 @-@

I bought a charging station for the Wii. It came with rechargeable batteries.

i have rechargeable batteries. its great cuz i have a bunch of batteries to use for my wiimotes, camera, wireless keyboard and mouse and cd player. i also use the older batteries for my tv, dvd and cable remotes and such. the only draw back is i have to charge the wiimotes batteries often but i guess its easier and cheaper to charge them then buying a pack of batteries at the store almost as often.

Rechargeable batteries should be the VERY FIRST purchase anyone buying a Wii makes. Using regular AAs would be a huge money pit.

As already mentioned, rechargeable batteries are a must with the Wiimote.

I highly recommend the Eneloop rechargeable battery line by Sanyo. They are new to the market, and their claim to fame is that they lose very very little of the their power passively (meaning that they won't lose much charge when your Wiimote is sitting there not being used).
http://www.eneloop.info/

The problem with every other rechargeable battery is that it will lose quite a bit of charge when you're not using them.
http://www.stefanv.com/electronics/sanyo_eneloop.html

This is particularly good for my family, because we have four Wiimotes and only two usual players in the house -- the other two are for when friends join us. (And for convenience, the two spare Wiimotes stay in our two Guitar Hero controllers.) So depending on how often we have people over, or whether we're on a GH3 kick or into a phase of some other game, those other two Wiimotes with rechargeables would lose a lot of juice just sitting around. But not with Eneloops!

Apparently, Sanyo is so confident in their product they even ship the Eneloops pre-charged (to 75%). So you can start gaming right away.

Beware of the the Wiimote chargers. Every one I'm aware of has numerous known issues with over-charging, frying your Wiimote, etc. (sorry, don't have a link -- but read the user comments for the various models on Amazon, etc.)

The special Wii-remote charging stations/packs use cheap batteries that only hold half the charge of regular quality AA NiMH rechargeable batteries.

I think they might even be el-cheapo NiCads but they don't actually say (but that's part of the reason I think so).

Most important things to look at is the milli-amp-hour rating (mAh) and to get Ni-MH batteries. I use 2200mAh Energizer rechargables, I find they last nearly as long as duracells. If you get cheap rechargable batteries (there's loads around of 850mAh) then you'll be very dissapointed with their performance. Trust me, spend the extra cash and get at least 2000mAh beasties

Oh and make sure you have 2 more batteries than you need (i.e. if you have 2 wiimotes get 6 batteries) then you can have a fresh set of batteries on standby