So I want to boot off my MMC card so I can have more room for apps.
But I also want a large storage area that is accessible by windows, so I can copy movies easily.

I was reading "HowTo EASILY Boot From MMC card" and it says to partition your memory card, but it doesn't give a reason why it needs to be partitioned, or what the partition are for.

So do I need two partitions? If so, what is the best configuration for what I want?

(I tried searching the forum for this, but I didn't come up with anything)

Thanks

Yes, you need two partitions. First partition will be formatted as FAT, so Windows (and your tablet) can access it. The second partition is for the operating system. The OS is Linux, so this partition should be ext2 or ext3.

how big(in general) is the actual uncompressed OS on the card itself?

Im guessing that space +100 MB should be more than anyone would ever really need otside of massive amounts of maps or games.s.

approx twice the size of the system in flash

300MB or more may be a good choice. On my N770 hacker edition with few installed apps it takes ~200MB. N800 with similar set currently takes ~240MB.

Depends what you want to have there. Most data can be kept on FAT partition (media, scummvm games, ...) which is easier to share over USB.