SMB1 Versions
So, you want to play Super Mario Bros. but don't have an NES? Well, there's still hope!
Super Mario All-Stars
SNES (1993)
The first reincarnation of the game has different graphics, but in exchange for this, you get SMB2: the Japanese Version which is a lot like the first one, only way harder (also with different graphics.) Kind of hard to find and you'll have to pay more than usual for SNES games. Super Mario All-Stars also has a version with Super Mario World, and that's worth even more.
Super Mario Bros. DX
GBC (1999)
The Game Boy Color is Nintendo's lost handheld son, but it does have some good games for it, like this one. The graphics are the same, but to put it on a square screen, the trade off is a smaller play area. Also has a version with red coins and Yoshi eggs to find hidden in each level. Also contains a fortune teller, sprite images (presumably for the Game Boy Printer), and a calendar from the years 0-3000!
Super Mario Bros.
GBA (2004)
Plays exactly like the NES version, that's because it IS the NES version, emulated, and put on a GBA cart for your enjoyment. When first offered in the market, it was only $19.99 but now is worth $10 more!
Super Mario Bros.
Wii (Virtual Console) (200?)
Yep, SMB got a release on the Wii's Virtual Console.
Super Mario All-Stars
Wii (2010)
Basically the SNES version (minus Super Mario World) on a Wii disc. Also contains a bonus musical CD (not for the Wii, but for a CD player) that has Mario tunes on it, from Super Mario Bros. all the way up to Super Mario Galaxy 2. Tracks 11-20 are sound effects from the Super Mario Bros. game.
Super Mario Bros.
3DS (Nintendo eShop) (2011)
SMB is a downloadable game from the Nintendo eShop. It costs $1.99.
NES Remix Pack
3DS/Wii-U (2014)
Not only are there tons of minigames based on the game, there is also a complete backwards version of it where not only do you go left instead of right, you're also Luigi! It's under NES Remix Vol. 2 in the game.