The new Gen 5 games, where to start...
The story, is excellent. Probably the best pokemon story since generation 2 came out to be fair.
The new pokemon will have you going back to the days of red / blue / green / yellow, where you have absolutely no idea what type the pokemon you're staring down at is, fantastic.
The graphics are much improved too, the moving sprites are very good, (they are pixellated on your side because the screen zooms in on your pokemon) and the sound is great too (The Team Rocket theme you will eventually come across is cool too).
The gym trainers, can be brutal, as most of them pack the typically overpowered pokemon we've had to fight before (Haxorus, Excradrill),
Then there's the elite four, they aren't too hard the first time around,, but the rematch is alot tougher, all are lvl 72+, making the first few runs for xp very challenging.
One more thing, Cynthia is brutal. =D
Hugely recommended game, will have you plugging in hours here there and everywhere