There are different styles of play. I have been in games that essentially were board games with a visit to shops in between the exploration and combat. I have also been in games that barely touched the dice at all and combat was handled by DM fiat after the players laid out their strategy in very broad terms. Both types can be fun, depending on your personality/mood at the moment.
The Storyteller System used by White Wolf for the old World Of Darkness series struck me as a very good balance between the two, back before children and grad school essentially put an end to my playing.
You say "grown" but D&D originally pretty much was a board game primarily. It was only with the later AD&D that things started getting further away from the classic dungeon laid out on a table using miniatures style play and more towards what most old school RPG players might think of when they hear the term "role playing game". And by "RPG" I'm referring in this case to the non-electronic versions played out of books, such as AD&D, any of the Palladium RPGs (Rifts was my favourite) or the original Champions for examples.
For gamers who are interested in the burning wheel aesthetic but are intimidated by the crunch of the system, I would suggest starting off with the Mouse Guard RPG ( http://archaia.com/blog/titles/mouse-guard-rpg ). It's not a 'lite' system, but it is a boiled down variation on the BWRPG
I am dying to get a Surface at home as a coffee table that handles the obvious stuff (photos, music, videos queued to the TV), plus other things like large-format TV guides, weather, bit of home automation, etc. Then add on stuff like home logging (entries whenever lights were switched on/off, front door opened, mail dropped in letterbox, garage door opened, etc) and security (manage security cameras and check videos of your frontdoor while you were out) and so much more.
And to keep this remotely topical, I think Scrabble and then 1-6 player Risk would be great also since I'm seriously addicted to playing Lux on my iPhone...
Any guesses as to how far we are off for these sorts of things? I'd love to see a line of Surface machines on the market and an app store for them.
Surface is still active? I've heard squat since it first appeared on the screen, some two years after identical techs were being made all over by the DIY crowd. Last I saw of it, it was still frickin' huge and projected to be really expensive, while the DIY options are simple, small, extensible, and cheap.
That said, interesting interface for the game. Seems like it'd be well suited to Warhammer too, given the firing maps & rather complex rules at times. A graphical overview could really enhance strategy.
There was a competition at one point put on by MS I caught wind of involving developing a killer app for Surface. The prize was pretty hefty, and I haven't heard of results, so it's possibly ongoing.
For people who want to emphasize storytelling and role-playing, I recommend checking out Burning Wheel:
http://www.burningwheel.org/?page_id=2
That's not to say you can't do good collaborative storytelling etc. in d20, but Burning Wheel has explicit structures & rewards for doing so.