Yes! Join our Death Guard-y ranks!
BASICS
LOTS of 20-man tactical squads w/ extra
CCWs and apothecaries for them.
LOTS of terminators of any variety (out legion specific ones are AMAZING and are stupidly cheap for what we get)
LOTS of Dreadnoughts. Mortarion liked them, so you should too!
LOTS of Heavy support squads, vindicators, and other heavy artillery
LOTS of phosphex, 'cause poison is fluffy and fun
Thoughts on
tac squads: I'd say the melta bomb isn't really worth it, unless you fear a dread slamming into your
tac squads. The vox is great if you ever have any artillery or deep strikers, and the standard (vexillia,
BTW) is almost an auto-include as we don't have
ATSKNF. It's also a good idea to give an attached apothecary an augury scanner for that juicy interceptor.
for 60-marines, I would do something like this:
2 20-man tax squads (w/ extra
CCWs,
AA on srgt, vox, vexilia, and p. fist on srgt)
1 10-man vet squad (I like 'em w/ 2 heavy bolters, but don't rely on these guys to be your main line infantry. think of them as more a percision tool since they are so squishy in 30k)
1 5-man support squad (meltas would be fun) or seeker squad
3 converted apothecaries
and you would have 2 spare bodies left over.