I did a search recently, and it seems the issue of apps hanging at install/download isn't isolated to any particular phone or even whether it's stock or running a custom ROM - It seems to be a major glitch in GApps, and they don't respond AT ALL to the numerous complaints. You can have one phone running perfectly, and an identical model sitting next to it, and there may be one or two apps causing a hangup, and it's stuck there.
I just did something that cleared the "Computing..." in everything under Manage Applications: I went in and Force Closed and Cleared Data in everything related to Google and/or Market, shut down the phone, pulled the battery, and everything appears back up and working again, for the time being. This may or may not be a fix, but I'm not doing any more wipes/reinstalls now that I know it isn't related to that process.
