I voted for Action Points mostly because I really like the concept that every so often a character is able to pull a little more oomph out of their pocket for an important fight/event, making for an incredibly epic moment. Though I would probably move them into "daily" type abilities. Epic moments should be truly epic, and being able to have an action point every encounter might be a bit much.
I voted for Healing Surges because I like the concept, but not so much the execution. As above, I believe characters should at times be able to cheat fate and pull off extraordinary escapes and recoveries. I don't like Surges tied into healing, it just feels artificial. I'd rather players had few Surges to make for rare, but incredible epic moments.
I voted for both Vancian and non-vancian systems. I believe that both systems are very functional, and there are enough types of casters in D&D to easily allow different ones to utilize different systems. Perhaps Wizards would use vancian magic, and Sorcerers would use a "powers" at-will, encounter, daily system.
Critical hits are a must. There's a 20 on that die for a reason. Critical fumbles are well...a bit of give and take. No real penalties for them means they might as well not exist, but penalties can easily be too heavy-handed as well.
I like Prestiege Classes and I like Paragon Paths, and I would like to see a compromise between the ability to pick up certain feats that allow you to become a Knight of the Rosebush as well as some "default" system that provides a higher-tier to your base class. I don't feel players should ever have to be anything other than the class they chose at level one to be effective at what they want to do(ala pathfinder class design). But I do feel that the option should be available largely for flavor or customization.
IE: a player should be able to be Rogue 30 as easily as they could be Rogue 7/Night Stalker 5/Shadowdancer 18. While they may have significantly different abilities in the end, players should be able to stick with what they like as much as they should be able to try out new things without totally rerolling.
I like saving throws as much as I like NADs, they serve two similar, but different functions and if I had my way, I would have both in my ideal system. Direct attacks, be they magic or mundane should be against NADs. Indirect attacks, such as blasts and explosions, should allow for saves.
I like skills, I believe they put down in words a way for players to identify ways to solve a problem. I may not think Dexterity would unlock a door, but if I see that the book says Dexterity determines my skill in Lockpicking, I can connect the dots that Dexterity makes my fingers more nimble and thus, better at handling sensitive tools; than if I just had to guess until my DM said "that one".
I also like feats, I think they are an important level of customization. We just need to make the default math better and get rid of 99.9% of the "math feats" and bake them into class/theme/background/role features. IE: Taking the Slayer background and the Mercenary theme along with the Fighter class increases your damage and to-hit. Taking the Guardian theme with the Devout Protector background with the Paladin class gives you the defender aura, a bonus to saves/AC/NADs, and better AoO.
There would be some minor feats that may give flavorful situational bonuses to hit/damage/defenses, but math feats would by and large be eliminated in favor of class features that are automatically delivered through package choices.
Feats would remain the realm of interesting and flavorful customization, such as getting your character wings or "Clever Tail" or other interesting, creative bits and pieces to allow you to better define yourself by your race, class, background, theme, or role.