R# 5 is looking good.
I discovered by accident (in VS2008), when navigating to an MS class library symbol that R# auto downloads symbol sources and displays the original MS source code which is extremely cool. On further investigation I found the R# option page above.
I should note:
1) Notice the warning? I haven't setup symbols in VS2008, the VS options/enable source server support checkbox is unchecked and the symbol path isn't defined, so should it be working? I think this is what caused RSRP-130230 on my system (duplicate of 125574) because symbols were downloaded to a folder with a long pathname.
2) The same thing doesn't work in VS2010 and I get metadata displayed. Even when I enable source server support etc I still get metadata.
By the way, navigation by Ctrl-Click works in VS2008 for R#5 but not in VS2010 is this intentional or a bug?