Well, the best ones are definitely the snipers; I don't like the Titans – they deal too little damage for a 7th-level unit, even though they do shoot...
Seriously?! And who else on level 7 have you seen dealing more damage?
I also don't like Cyclops – 20 crystals – it's better to upgrade the bears:p
Well, then 30 ;) – build them first.
I also like (arch)mages; they are expensive to build, but they are worth it.
Don't even bother looking for alternatives here – the old men are awesome! If I'm not mistaken, they are the second best out of the 4th-level units, after vampires ;)
And in general, the best shooters are azure dragons:p :p :p it's a pity they can't shoot:D :D
They can, they just keep forgetting their arrows at home :D