I found super mario brothers 1 the easiest personally.

Basically what ghost of rubang thinks

Length of fastest speedruns, longest to shortest:

Super Mario Bros. 3 (11:01)
Super Mario World (10:59)
Super Mario Bros. 2 (9:15)
The Lost Levels (8:34)
Super Mario Bros. (5:00)

Seems the games had a trend of getting longer and easier.  Jam-packed with more content, but not as frustratingly difficult.  If New SMB Wii is harder (thanks to the Super Guide) AND longer than Super Mario World, I wil be very very happy.

I've just been playing NSMB Wii for the last 2 hours. 2 player and singleplayer. I can't wait to get back to it. Avoid any reviews with spoilers, the game has some really nice touches that will bring a smile to your face.

For anyone who gets a chance to play soon, down + 1 + shake = pick up other player, keep 1 pressed down to carry, release 1 to throw (like a shell). It was the first thing I wanted to do but I didn't learn it until 1-2. We played 1-1 about 8 times before moving on. I could play the first level for an hour and not get bored in multiplayer. Mario Deathmatch is fun.

Has anyone finished this game yet? I'm stuck at the end of world 8. It's a lot harder than I was expecting.

Hmmm.

....I'll pick this up tomorrow.

Sorry, SMB3. You may be put on the back burner a while.

Did people break street date or something?

Plenty of stores in AU broke street date. The game is available all over the internet now.

Are you saying you have a pirated copy?

The way you guys were talking I just thought I had misremembered the release date.

You can't really use speedrun records to gauge the length of a game since such runs allways skip a majority of the content. I think you're still right though - games get longer, and easier since they no longer need the player to fail repeatedly in order to artificially lengthen playtime.

NSMB Wii might indeed have the best of both worlds, but I'd expect a SMB3-like experience, personally.