If you can find it, I would suggest starting back up with HeartGold or SoulSilver. They are remakes of the second generation of the series and would be a great games to jump back in with. Along with lots of new Pokemon and a new map, the game also features the land as well as the Pokemon from Yellow Version, so not everything will be so foreign.
Pokemon in those games can also follow you around, similar to Pikachu, except you can choose which one is out of their Pokeball.
I highly recommend Black or White, it feels a lot different from HGSS (not in a bad way). The majority of the game only features new Pokemon which turns off some people (if you fall into this camp, Black 2 and White 2 remedies this), but has lots of throwbacks to the first generation in a lot of unique ways such as character design and music.
If you want you can wait until X and Y are out, but you really can't go wrong with any of the main series Pokemon games that are available right now. :yes: