Since you just go for the guests, citrus, I'd recommend sticking with the smaller, "less than 25K" cons. 25K is my cut-off for most cons; After that, it just becomes a massive gathering and any goals you had at the con become next to impossible unless you're willing to line up hours before an event. Or, like AX, you pay extra for a ticket that gives you expedited entry (the 'Premier Pass'...which is largely useless..) With a lot of cons, money does talk and you get expedited service if you're willing to spend that extra buck.
Cons like Animazement, SacAnime, SakuraCon, YaoiCon (fun con..), PMX, Anime Detour would all be venues I would look at. I've yet to attend a Midwest con, but Wikipedia shows that they do get large numbers. IMO, the smaller the con, the better it is. You get to have a lot more quality experiences with the guest as opposed to being lined up like cattle for panels and autographs. The downside is that, if you're traveling to go to these cons, you're paying more to meet each guest and for the experience.