Thug Commanders

[Sombre]

Thugs - Black Servant, Bane, Banelord (straying into lesser SC territory here), Sleeper, lesser angels, any tough recruitable commander like a sidhe, even LA Ulm's Hochmeister etc

Basically anything with a decent number of combat advantages and itemslots at a low cost.

[Agema]

I'd do a bit of SP testing with thugs.

Personally, I think the key to thugs is that you're expecting them to take out large numbers of basic units who don't have magical weapons or mage support. I'd say a decent thug should be able to kill at least 10 points of PD comfortably.

They need to either avoid being hit (e.g. missile shield, awe, ethereal) or able to resist damage when hit (25+ protection, mistform). They should be able to kill quickly, more than 1 enemy per turn. If they have high encumbrance, they'll need reinvigoration. If you know your opponent has some sort of aura (eg. fire for Abysia, cold for undead), you need the appropriate resistance.

Thugs tend to have limited HP, which also means regeneration is often limited use, so don't go out of your way. Similarly you shouldn't be spending gems on non-essential elemental resistances or magic resistance. The exception might be something near the thug/SC borderline (e.g. a banelord) which is worth investing more in.

For a great bit of info how to turn units that don't at first seem very dangerous into nasty thugs, Baalz has a guide on Eriu (Tir Na Nog?) which has some pointers with their Sidhe and Tuatha.

[Bwaha]

My favorite thug is a gift of reasoned gargoyle.

[Rytek]

My favorite thug is Bane Lord
Boots of flying, jade armor,frost brand, any shield (my prefered is the lightning shield), pendant of luck, pendant of MR.
A fearsome raider indeed. especially if your opponent has no access to anti undead.