One of the big attractions of Grand Theft Auto, at least so i've heard from everyone who's played the game and spoken out about it, is just running around causing random mayhem. Jacking cars, shooting people and things, driving a semi through oncoming traffic and off a pier, etc. I've heard actual complaints about the ongoing development of story based elements in the game. Either you're playing someone who's climbing their way out of a moral sinkhole but with interspersed fits of totally out of character mayhem when you decide to go on a joyride (GTA3 San Andreas, or so i've been told) or you're playing someone who'd diving headfirst into a moral sinkhole and for whom random fits of mayhem are totally in character, but who is really hard to sympathize with because of it (GTA4, or so i've been told.)
(Also, the focus on story has apparently led to all kinds of bad and nonsensical gameplay decisions, as Shamus Young of "the DM of the Rings" fame comments on here. (Or maybe it's just bad gameplay design for bad gameplay design's sake, i don't really know.) All in all if i'm going to get a GTA type game for the PS3, it sounds like it definitely ought to be Saints Row 2.)
All of this is easily avoided with a Lego version. I think everyone who ever played Star Wars Lego spent quite a lot of time killing and maiming their Lego "buddies" and laughing at the comical way they would explode into Lego pieces, or hop around on one Lego leg, or go plummeting off a cliff into lava. Especially if it was JarJar. No one ever feels bad about it, because they're Legos! (And in the case of your buddies they come right back afterwards anyways.) And can you imagine driving a semi down a street and crashing into things and Lego pieces flying everywhere? You shoot someone and they explode into Lego pieces? Maybe you could snatch a purse, and the person's Lego arm comes off with it? It would be totally awesome.
(This would also avert my personal pet peeve with GTA4 and a lot of the other "next-gen" games, that it looks way too realistic. I just like cartoony looking stuff. (According to my parents i latched onto animated stuff very early and never let go, while my sister preferred live action stuff more.))
All of which is really just a long winded way of getting around to what i _don't_ particularly want.
Lego Rock Band. SRSLY. WTH? How does this make any sense? The only advantage i can see to it is that it would eliminate the stupidly realistic look of the band members they've been going for in more recent versions of the Guitar Hero/Rock Band franchises, but i know that's a personal aversion that isn't shared by most of the rest of the people out there. The really sad thing though is when i look at the current song list, abbreviated as it is at this point, and think "that looks pretty good actually." Hopefully when/if i get Rock Band i'll be able to buy those songs as DLC without buying the whole other game. Or alternately since i don't actually have a copy of Rock Band already i could actually _start_ with Lego Rock Band, since i don't actually object to the concept in principle, i just don't think it adds anything worth buying a whole 'nother copy of the game for.
And while i'm on the subject of what the hell were you thinking, i'm baffled by one of Dunkin Donuts current ads. Some kids are literally getting their souls sucked out of them by just sitting there dumbly watching TV, but don't worry! You can save them with the natural enemy of mindless entertainment! Doughnuts!!! SRSLY? I mean i like doughnuts, but i like tv too, and they _both_ fall into the same "i like it even though it's not really good for me" category in my mind. Sitting down in front of the boob tube with some donuts and feeding both my mind and my body junk food seems like a perfectly natural combination to me.
(And this is totally aside from the fact that i get aggravated by both Dunkin Donuts and Sonic bombarding me with an endless series of commercials extolling their virtues when there isn't a single store of either one of them within at least 100 miles =P)
Also, you know what? Katamari Lego would be pretty cool too :)