I only do ep1 cmode because I enjoy the different looks of the ep1 S-Ranks. I have so far:
Drizzl Sword +250 for my HUmar, has Berserk
Nomads Rifle +220 for my RAmar, has Demons
Loaded Twin +200 (/250) for my RAmarl, has Berserk also.
Berserk IS a popular special choice, and it's a nice one to use unless you're a total berserk abuser and waste your FO's time making them keep a constant eye on you. Personally, my rule of thumb is be ready to heal afterward... which is why I don't berserk with my droids. Anyway, I would've gotten spirit on my RAmarl's twin, but I'm not too familiar with it, and she uses plenty of TP as it is.
I'm not too sure what to make with my fourth S-Rank. My HUcast and HUnewearl would probably be next in line to recieve one, but both of them already have good-hit twin sabers (30 hit cudgel, 45 hit demo comet), and swords/partisans (25 hit chainsawd, 30 hit red partisan). So I'm not sure... :ermm: maybe my HUcast could use something a little rarer than his 20h God Hand. But what special would I put on a saber? For a cast, that is... maybe zalure? Arrest? Hmm...
Anyway, for you I would suggest whatever you might need that doesn't particularly require hit. My HUmar manages with his S-Rank Sword, but isn't terribly good with it. Sword IS very powerful when grinded... but I wouldn't get it on a HUcast or HUnewearl, they probably won't hit very often with it. For twin, I would only get a twin for the special, as hunters can use more powerful twins like BKB and Double Cannon (or whatever is good in ep4). For a ranger, a rifle or a mechgun might be nice, or shots if you like them; personally I find shots way too slow and I much prefer needles... but of course since I don't play ep2 cmode all my rangers carry spread needles. I don't mind this, though, because the SN special is pretty good. For a force? Erm, don't get an S-Rank for a force, I'd say.

They'd do much more good on your hunters/rangers.