That's what I'll be waiting for as well. Until then, I'll run with 2.1 and Sense.
Froyo looks awesome, but I doubt the wait will be long and I'll have more than enough to sink my teeth into with 2.1 and Sense to keep me going. Froyo will be a VERY cool upgrade, but it doesn't have any GOTTA-HAVE-IT-NOW utility for me. The performance increase will certainly be amazing, but from the reviews so far, the EVO's hardware has handled the software load just fine.
Actually, I'm pretty sure that exact ability with 2.2 will be what delays the update coming to EVO. Sprint will have shot themselves in the foot. I'm sure we can assume 2.2 won't port Wimax connectivity (but someone will find a hack), but the fact it gives 3G tethering will be a turn off to Sprint as it's undermining a target market for revenue (they're marketing the phone and service in all coverage areas). Pretty sure 2.2 with EVO will have the tethering aspect disabled (or perhaps with every Sprint phone, though that's a reach) out of spite. ..Though, if they don't then that'll be awesome too.
The 3rd option kind of defeats the purpose of the original question. When it's possible to have Froyo and Sense on a rooted EVO, that seems like the obvious route to go. I'm trying to decide what I want to do until then.
I like the plain version someplaces and Froyo fixes the "launch bar" so that makes it better.
plus some of the HTC apps I won't use, footprint, frindstream, peep, so it's just bloat.
I'm sure we'll see a cyanogen mod for this beast.
The question is after Sense's eye candy could I give it up?
I can't vote yet.