What a great dilemma to have. AT&T users like me hafta search around online to find something unlocked. I was seriously considering switching to Verizon before getting my phone (Acer Liquid, very happy with it) so I did do some researching around.
If you can wait out the summer you should (depending the deals on your upgrade offer). That Moto Shadow could be an attractive option.
As for Droid v Incredible, depends on what you want. Both are high end phones.
If you plan on hacking (will void warranty), Droid is the best option. Droid can be overclocked to 1.2GHz and with a better GPU, is a better option for gaming (if you are into that). Droid overclocked at 1GHz v Incredible linpack results here-
YouTube - Motorola Droid vs Droid Incredible 2 - Wifi Fixed and Linpack (both are fast, Droid proves to be faster. Infact, if you see all Linpack results, all of the top ones are Droids, probably overclocked super high). Also alot of ROMs out there.
If you don't plan on hacking, Incredible would be faster (as CPU is already clocked at 1GHz). SenseUI is very good and that AMOLED screen is beautiful (tho LCD reacts better to sunlight but how often do you look at your phone in direct sunlight?). Also 8GB of on board memory is a big plus (especially after Froyo comes out). And if you care about cameras, Incredible has a 8 MP camera w/ Dual LED Flash. It also has video out (if you care about that. Don't know on the Droid, read that it does not)
Both Motorola and HTC have said that these devices will get FroYo updates. Neither have given an exact timeline. Tho both were pretty slow updating it to 2.1 (Droid upgrading from 2.0 and many HTC devices upgrading from 1.5/1.6. No idea how similar or different the FroYo upgrades will be). However, there is a rumor floating around that the HTC Desire will be getting the FroYo upgrade on June 23rd and if that is the case, my best guess (no proof of this whatsoever, so take it lightly) is Incredible gets it around the same time (as they are very similar). Important thing is, both of them will be getting it.
Hope that helped.