I have a friend who is trying to make the switch to Linux, but is hung up on the apparent lack of debugging/IDE environments for C++, especially as they relate to template progr
About 7 years ago I used KDevelop that was shipped with KDE. I found it quite good back than, and I hope it also improved with the time. I found it quite comparable to VC++ 6 at this time.
It also contains Qt support, if you are in need for some GUI toolkit.