Tessa, your top ten is my top ten, although I think I'd organize a bit differently.
I also think there are tiers. ABT and NYCB are both a bit problematic at the moment, but as institutions, they're at the top.
The next group would be:
San Francisco Ballet
Pacific Northwest Ballet
Miami City Ballet
Houston Ballet
Boston Ballet
I think what Tessa posted -- that the last two are wildcards because of changes in leadership -- is an important point. It's what separates those five from ABT and NYCB, for me, both of which have survived changes in leadership (I know that point is debatable for some NYCB fans, but the company is still dancing and its repertory is structurally, if not always qualitatively, within its traditions.) SFB is in good shape now -- although it's lost a lot of dancers. And its repertory is turning more and more to contemporary dance and away from ballet. PNB also has an uneven repertory -- and what will it be like under new direction? Miami has the sternest backbone -- it's as Balanchine company, goldarn it, and that's what it is -- but has financial woes.
Boston isn't quite a wildcard, because Nissinen's first new season has been announced, and it looks like it's going to be SFB East. Whether Boston will go for having their Russian-tinged repertory replaced with lots of New Now Dance and European faux classics (the Van Dantzig "Romeo and Juliet") is still an open question. Houston is wide open. Whatever one thinks of Stevenson's ballets, they're popular at home, and if someone comes in who wants to replace them with My Very Own Ballets, that could turn out to be a problem.
Ballet West has been left out of these discussions -- it's a quiet company now; it doesn't tour as much as the other biggies. But its budget is in the same range, it has good dancers, and its repertory is similar to Boston''s. I think the Joffrey should be in the Top Ten too -- as much for its history as its reality, although I think the company is on its way up rather than down. It takes a long time to recover from something like Billboards
The next group for me would be Philadelphia, Pittsburgh, Cincinnati, Atlanta, Colorado Ballets. Companies with big ballet repertories that are popular at home, but don't get out much, and don't have a consistently top level of dancers.
Then you have Oregon Ballet Theatre (also a wildcad, as its raison d'etre is packing it in), Washington Ballet (on the way up in terms of budget, but Webre is not, in my estimation, a good choreographer), San Jose-Silicon Valley (if the money holds, they'll be a player), Ballet Arizona (all they need is money; but Ib Andersen has turned that company around in two years, and IS a good choreographer), Milwaukee Ballet (had a recent personality change, going from a Saturday Night Out repertory to a contemporary ballet rep) and Carolina Ballet, which is being built very solidly, although I remain to be convinced about Weiss as a choreographer.
Apologies if I've forgotten one. I can't judge Oakland and Tulsa; I've neither seen nor read enough about them. There are also some small groups, like Ballet Florida and Ballet Austin, but I don't think they're into the major leagues yet.