Some additional thoughts even if it's just building up on what people have said allready:
STR potion, Reflex and Quicksilver - Preppin these 3 for heavy prep runs gives you awesome powerleveling capabilities. I've overused this so much I'd nerf it.
Burn Salve - was an autoprep for me because 1) it takes away the penalties for Martyr Wraps which is THE most damaging item in the game for resist stackers and 2) Makes any EM altar free piety + 3 indulgences.
Picking up STR, Reflex, Quicksilver, Burn Salve and Whoopaz is what I do most often as far as potion preps go, and if they end up combined with Alch Scroll and/or Tri-Sword then it's just silly.
I mostly don't prep Tri-Sword though, because of the:
Quest items prep - depending on your state of unlocks, this is almost cheating. The pool can look like this - Martyr Wraps, Tri-Sword, Soul Orb, Viper Ward and whatever is unbalanced ATM (I used this approach to guarantee Mage Plate and Platemail quite a lot).
Potion fueled items and the Quest item preps benefit from +1 gold per pile prep, as do any CP strats, especially ones involving tinkers. Extra gold is probably your best bet unless specificaly wanting patches, or if you really need the exploration from the extra subdungeon.
This hasn't been stated enough - EXTRA GLYPH IS RIDICULOUS. It really is. watch this:
1) You get more chances to find a glyph you want. If you want to keep a glyph (and yo ussualy want to keep one) it means 80 CP "unutilized" rather than 100, if you convert the rest.
2) For goblins specifically, better controll over when you ding, as you keep the same total ammount of glyph CP in the dungeon, but it doesn't take you over the threshold on it's own. For Wizards, this simply means you get more variety.
3) It means more piety! Noone ever mentions this, and this is where it breaks the balance the most - you get more certain piety with GG or Taurog (who are good preps as well), and you get more chances to find APHEELSICK which converts well for GG and HALPMEH / CYDSTEPP which converts better for Dracul.
4) It means one more glyph for Mysterea's mana regen boon, which I consider silly with manamonster characters.
I almost got pwned by Shifty Brickwork!