I wouldn't really be able to say whats best on early game SCs (I tend to do one or two SCs in the late game and go all out and spend upwards of a hundred gems on each (sometimes more)
. I find the best items in the early game are path boosters and possibly survival items for mages (especially against archer heavy races, like man or races that tend towards offensive magic). Under Conceptual balance most of the late game items are fairly unaffected (the ones I take anyway) so it doesnt really change my choices. In the late game i doubt theres a better value than Amon Hotep (its summoning ability aside). Ummmm... what else? Quickness I find to be good only in one or two scenarios: SCs that dont get fatigued (or have someway of getting rid of their fatigue-I suppose that's most of them) and big bad undead killer priests (priests with spell foci (possibly a rune smasher too) and a high priest lvl). i find that with quickness all you really do is compress a seven turn cast orer into four turns, then you fall unconscious, whoop di doo. I find that regeneration is excellent but more for the health per round than the lower chance of getting afflictions, but again, that's more from late game experiance where I often have the chalice, gift of health, healing units (witches are fun) or an SC that will get rid of afflictions on its own (immortal or recuperative).