[rdonj]

It might help for you to make a list that you can refer to of items that give you the effects you want. So say you want items that grant reinvigoration. You have boots of the messenger (nature 1), amulets of resilience (nature 2), girdles of might (earth 1), and rainbow armor (air 1&nature 1, also gives magic resistance). Hopefully you will eventually learn the items on the list, or if not you'll at least have that handy reference to refer to. There's also forging references that have been made, but given that they don't tell you what the item does they may not be too helpful to you.

Reinvigoration is definitely very important for any thug that has encumbrance. As for ethereal, ethereal robes are usually best reserved for earth mages who can cast invulnerability or the like. Then they can have protection AND ethereality. Aside from robes there's just wraith crowns and artifacts to grant ethereality, and wraith crowns aren't generally good SC gear due to creating masses of skeletons that can cause lone SCs to rout. Another option instead is just to bring a low level astral mage along to cast body ethereal on your thug. Generically good SC gear would be along the lines of - an AoE weapon, shield of gleaming gold or vine shield, amulet of antimagic, luck pendant. Helms, armor and boots tend to be less generically appliable, and most times helms aren't necessary. The most generic boot slot item is probably boots of the messenger for the reinvigoration, followed by winged boots.

The last bit would require a bit more in depth of an answer than I really want to get into right now, and depends a lot on your nation. But in general you do want to have thugs in the midgame and SCs in the end game, but if that's all you have that won't be enough.