If you're used to the 'hackability' of the HD2, the last thing you want to do is buy a current HTC device. Believe me, I've been there
Their developer support is lame and their warranty policy is dreadful (and illegal in Europe, although I haven't seen that put to the test yet) the first thing they do when they receive a device is send you an invoice to repair or even return the device to you if it's bootloader unlocked, even if the fault has nothing to do with software. Plus, their idea of a bootloader unlock isn't really what most used to older HTC devices (S-Off) are used to...
I think the Nexus 4 is probably about the best option right now. It doesn't have an SD card slot. It doesn't have a removable battery (although the battery is pretty easy to replace when it wears out, it's just four screws and a bit of coercion.) Those two alone are going to be dealbreakers for some, and for the remaining people, the glass back might be an issue. I'm not going to lie, it's not ideal. I'd like the hardware of the Nexus 4 in the chassis of the HTC One X, myself (I don't like aluminium phones, they dent and look ugly in no time)
The only other things really worth considering are Sony devices - the Xperia Z looks pretty tasty, since they have a similar level of developer support and the company has made a really good effort to support the development community and AOSP in general. However, you have to be careful as operator branded Sony devices are locked down like Fort Knox (no bootloader unlock at all AFAIK.)
Samsung are going very much in the direction of HTC these days with regard to developer support (e.g. crap.) On top of that, I personally wouldn't buy a Samsung device because they keep releasing buggy hardware (S2, Note 1, S3, Note 2) with serious flaws that kill the devices, and their patches for these issues are a) dodgy code and b) don't appear to totally eliminate the SoD issue on the S3/Note 2. I'd be more forgiving if it weren't for the fact that the eMMC bugs traverse several generations of Samsung devices and now I suspect they just have crap quality control. I don't really like the idea of paying to beta test hardware for them :-/
LG Mako - AOKP PUB/STS Kernel | Asus Grouper - AOKP PUB/Faux Kernel | HTC Vision - Flinny CM10.1 | Barnes & Noble Ovation - CarbonROM
HTC EndeavorU (eMMC Corruption Brick) | Motorola Olympus (Cooked itself) | HTC Bravo (Sold) | HTC Dream (Retired) | Apple iPhone 2G (Retired as a music player) | HTC Hermes (LCD Died)
Free RAM is wasted RAM, foo!