Non-con play is essentially over (there are few guarantee games left, none of which should be close). If December was any indication I certainly expect a lot of home wins this year. 15-5 could be enough to win the league (maybe even 14-6).
Michigan, Ohio State, and Sparty appear to be the top 3 teams in some order (when healthy). All of them have some good wins and no bad losses (even Virginia Tech is respectable).
Iowa, Maryland, and Penn State also have no bad losses, but their wins aren't that great, either. All of them could be contenders, but I'm not sold yet. We'll find out soon enough, though.
I'm probably more down on Purdue than most people, but they're too inconsistent, and even the VCU and Virginia wins probably aren't as great as expected. Same with Indiana, which lost a game they should've been able to win at home against Arkansas tonight and inflated their record with a weak non-con schedule. Illinois also appears to be on the same level, as well, as borderline NCAA/NIT teams.
Wisconsin, Minnesota, and Rutgers can all beat anyone in the BigTen, but they're also just as susceptible to mediocre losses. Finishing 1 or 2 games above .500 still might be enough for them (or anyone else in the league) to make the NIT, though.
Nebraska and Northwestern are clearly at the bottom of the league with all of the bad losses. They still have a few good wins between them, though. They'll still pull off a few BigTen wins against the rest of the league. The bottom of the league has certainly been worse before, though.