JackSparrow, your choices are tough and correct at the same time! Pick one! I don't think you'll be ashamed of yourself if you just choose what your heart feels. I would go for TES4, though, just on the basis that I've played it for years and loved every bit of it.
Console: Super Nintendo Entertainment System
The SNES had such a great game library, but arguably had the BEST game library of all time, because of the high selection of highly-rated games. The console did very well because the games themselves did.
Game: Chrono Trigger. I just wished that others had the same zeal that I do about this game. It is ported to the Nintendo DS, so there shouldn't be any reason why DS'ers don't have this game. Why is this on the list? Because this is the highest rated game in existence. If you like RPGs, a vast storyline, and have a DS, go buy this. It's been on the shelves for a while, so it should be around 20-30 dollars at the most.
Series: The Elder Scrolls (soon to be giving birth to Skyrim!) Every time an Elder Scrolls game is released, it yields several Game of the Year awards and high scores. TES1 Arena was THE first game to employ free-roaming "do as you dang well please" mechanics as well as being one of the first games to install night/day technologies. From having a wide-range of quests, a wide-array of weaponry, and a large world mass to explore, as well as having many populated dungeons, towns, and caves to plunder, it's no wonder why this game, and the entire series itself, goes on my list of being the best series around.