No problems installing multiple versions on W7Prof+SP1. Thus have SS2005, SS2008, SS2008R2 and SS2012.

The only thing I watch for is that they are all named instances, in fact, I'm using the names you see above.

The other thing I do is set the TCP port using Configuration Tools/SQL Server Configuration Manager. Thus SS2000 (now de-installed) was set to 1433 (the default). I then went up one for each new SS version. Thus SS2012 is at 1437. And I'm about to put SS2014 at 1438.