Don't have a NES anymore - seeing NESTER run on the Dreamcast was so good I ditched the hardware - the NES being an 8bit really benefits from the improved display of the DC, save states and the selection of available games!!
I had one for quite a while and look back on it fondly though - would probably pick up a US or JPN console if the chance came up ...
Anyhow my favourites (inc. the obvious ones!)
Super Mario Bros Yeah a bit obvious - thing is - this game really is that good, Sublime control with spot on inertia and pixel perfect placement of enemies in great levels means it is still an excellent game after all these years.
Super Mario Bros 3 Epic next step in the series. The over world map, the powerup suits, flight, bosses and mini-forts - all that was introduced here as the template for the later games. In fact this game saw the Mario universe expand greatly - so many new enemies were introduced here such as the boo ghosts etc. A massive number of levels, great graphics and sound. That trademark control and physics. Still puts many later platformers to shame.
Gradius Great old port of the arcade game. Flickers in places and slows down in others- but it feels like the arcade. Rock hard challenge.
Punch Out Legendary comic boxing game - this was a real crowd pleaser back in the day. One of the few games that made ever me laugh.
Solar Jet Man Massive gravity based shooter in the same vein as Gravitar and Thrust - only this takes the genre to it limits. Filled with different planets to explore and items to find in your quest to find battle ship parts. Weird humour and sound effects make for a very pleasing experience. Technically brilliant too - huge levels made navigable by the mapping facility and smooth 8-way scrolling was a big deal back then.
Solomon's Key Excellent port of the Tecmo platform puzzle game - pretty close in quality to the arcade game.
Balloon Fight Nintendo does Joust - and in some ways improves upon it. Faultless sense of inertia and the cute balloon grasping characters are more fun - and there's variety in the little bonus levels. Great 2 player dynamics as in Joust. Also features an extra little game called Balloon Flight which is a survival style "how far can you go" game that is seriously addictive.
Tetris Nintendo's version is great.Pity there's no 2 player mode but its a brilliant interpretation of the game which isn't a given even now - many later versions don't feel as good as this one.
Devil World Excellent maze game which is a clever development of Pacman. Another game with a great 2 player simultaneous mode.
Battletoads Great in 1 player but a riot in 2 player. Technically excellent multi-format game. It goes from a scrolling brawler to a cavern decent, to a bike ride, to a trad. platformer, to a hori shmup, to a river ride on a surfboard...... Too hard for its own good in places but a really entertaining game.
Boulderdash The NES got a great version of this. Really slick presentation - I'd say the best of the 8bit era at least.
Donkey Kong & Donkey Kong Jr On one cart. Good value at the time! DK has 1 level missing (as most versions do for some reason) but the star here is DK Jr. I think its a better game and it is complete here - all the levels. Spot on conversions.
Dropzone Stunning redux of Defender by Archer Maclean - the NES gets a lightening fast version that looks great, sounds great and controls great. Just writing this makes me want to get a NES again just to play this.
Dr. Mario Original version of this underrated puzzle game from Nintendo. Not quite Tetris but it outdoes many efforts by other dev houses. Highly addictive.
Ice Climber Lovely little vertically scrolling 2D platformer. Great simultaneous 2 player mode that really changes how you play. Looks pretty good too - would like to see a remake of this.
NES open tournament golf Great later release for the NES. A full featured golf game with great graphics and control - ahead of its time.
Palamedes Clever dice based puzzle game with 2 player battle mode.
Probotector aka Contra War in a box - brilliant run and gun from Konami. Total action from start to finish and it has great variety in it levels. Has a 2 player simultaneous mode too.
Spelunker Cave based platformer with nice detailed graphics and a real sense of exploration. It can be a bit fussy - your character dies really easily (too easily in a fall) but its a great game and a hefty challenge.
Yoshi's Cookie and Wario's Woods Two top notch puzzlers that were late releases and so have really slick graphics and presentation.