Of the spellcasters I've played, I've traditionally gone with spontaneous over prepared in 3.5. I've played:
rogue then fighter/rogue (2e), and a ton of different stuff in 3.5 (off the top of my head, a wizard/swordmage gesault, a bard/chameleon, a fighter/ghostface killer, a rogue, a rogue/swashbuckler, a crusader, a fighter, a warlock, a warmage, a bard/cleric/divine prankster, etc ...) In general, when I did have a lot of choice for spell prep ... I was always prepping the same spells anyway, and I generally had the catch phrase of "I can do that ... tommorow". The DM'ing/adventure sort of made it hard to be sitting around making contingency scrolls or stopping to buy them in town, etc so that never became a strategy within the party. The curestick did get screentime.
In general, 4e fits into the style of play we were doing, and uses a lot of the "splat" parts of 3.5 we liked ... having the at-will ability of the warlock, or taking the reserve feat to give the other spellcaster an at-will ability, etc.