Aye, I agree, I take the mana potion on the end reward list quite often because it pops so much... over the past year I'd estimate at least 100-200 of them between my cleric, bard and wizard... in fact I think I've got them before on my ranger and pally - not quite sure. In comparison I have 3 +6 str belts, 1 +6 con necklace, 3 +6 cha cloaks, 2 +6 dex boots, I've not been so lucky to find a +6 wisdom item as of yet... however I bet I've run across least 10 or more +6 int goggles.
I used to get enough mana potions together and sell them on the ah... however anymore I keep them.
I do believe Glass' post though an exageration just intended to show they're not as common as a healing potion, which they by far are not.
I will state a few things though... from a wizards perspective... not a sorc. If the caster is put into the role of party support thru buffs - such as a wizard who general is because they cannot deny they have the buff in thier spell lists;-) It generally regulates them into a more passive role thru more of the quest because they wish to manage thier sp pools. Most sorc do not have this same problem as they're not neccessarily key buffers. When alone or short-maned the SP pool actually becomes more viable on a wizard for DPS... thus you can take a more active role in the group just by limiting the number of other classes who may ask for a buff.
I do not advocate any nerfing to any class... but i do forsee a problem unfolding in the future, and what we do see is it's just starting to unfold. This is a fact... Arcane casters will get more DPS power from this point forward... melee will not - unless they pass it out through items... the BaB goes up on melee and the number of attacks also (but they've already showed they're slowing them down - more attacks = less over same period of time)... however the damage per attack will not rise really - by just a few points ie.) +2 more str and +2 for mighty rage. While it's true other classes have incoming feats ... ie a fighter has 5 more coming to 20. None of them attribute to dps in any great resort. Whereas the arcane also get 3 feats coming but also about 100sp per level and 2 more levels of spells. I do not know if you think of it this way or not... but every spell in your list is comparable to a feat or a weapon.