The Chaos Space Marine codex has some nice heavy support choices. Some are old favourites which have been around a long time and have imperial counter parts and others are funky new stuff. I am going to look at two particular heavy support choices; Havocs and Obliterators.
Havocs
Dark Eye Studios
Havocs are CSM Devastators. Nothing really special going on standard wise with the Havocs.
The weapon options is where is it at for the Havocs, here they become extremely customisable and can fit into your army and plug the gaps.
If you are doing an old fashioned Rhino rush list then these guys can fit in; take quad meltguns, plasma guns or flamers if you like.