If you have a few hundred laying around, I'd highly recommend getting a mixer to go with your 828 if you haven't already. I have a 16 channel Mackie and it was worth every penny.
If I'm doing a whole band's worth of tracking at once, it looks like this:
For channels 1-8:
mics -> Mackie 1604VLZ Pro -> MOTU analog -> PC running Sonar
For channels 9-16:
mics -> Presonus Digimax* -> MOTU 828 ADAT -> PC
For channels 17&18:
mics -> FMR RNP -> Midiman Flying Cow -> MOTU 828 S/PDIF -> PC
For monitoring:
Aux 1-4 and mains output -> 4 channel Behringer headphone amp -> headphones
If I'm just tracking 1-4 sound sources (overdubs, etc), the setup changes a bit:
mics -> FMR RNP and either Presonus Bluetube or the Mackie's preamps -> MOTU analog -> PC
Monitoring:
headphone out on the MOTU -> Mackie -> headphone amp -> headphones
If it's something that's a keeper, I always go for the FMR RNP over the preamps on the MOTU or the Mackie or the Presonus gear because it sounds better and allows me to reverse phase on the fly without having to build a special XLR cable for it or do it in Sonar after the fact.
I have this set up in my basement and I try to shanghai everyone into practicing at my house, so I record all rehearsals this way regardless of who I'm practicing with. Being in bands that don't record rehearsals is a pain. Many moments of brilliance which otherwise get lost and many "you screwed up!" "no, you screwed up!" arguments which would otherwise spoil practice are easily averted this way.
I don't bother multitracking the vocals for practices, I just mix them down to a sub channel and record that. Even with everyone in the band singing it's not like you're going to release your practice recordings anyway. With drums I'll burn four channels on snare/kick/overheads because a lot of the time if the drums sound bad then people will think the whole thing sounds bad if they don't know what they're supposed to be listening for. Plus I find it to be useful when going back over jams and picking out things. That leaves me with five channels for guitars/bass/violin/mandolin/whatever.
I also record at 16/44.1k even though the MOTU and friends will handle more. CD 'quality' is fine for rehearsals and saves disk space.
* I don't usually need more than 10 channels for anything if I'm creative about how I set things up. So if I have to make the jump I'll buy a Digimax off of ebay and then resell it when I'm done.