Jeff - sounds to me like she's run out of options and is coming back to where she feels most comfortable.
There are two posibilities here: she tried her other Ex's and got shot down, or she liked you best. You need to find out, by any means necessary, which is true.
If the latter, then you have a special case here and if you still have feelings for her it would seem prudent that you give things another chance, BUT BE CAREFUL. Don't lavish her like you used to, but don't be so distant that you ruin it. You need to make sure history isn't repeating itself before you recommit. Make sure she understands this, and is okay with it.
You and you alone make the call here, she came to you - find out why; and make your move before she disappears again.
Sig shamelessly stolen from [e]nigma.
<st10r`> I can't believe Jason has the heart to go on
<coL|1`RIOT`out> I do
Sup just sippin a natty workin on my brocabulary