Depends. There's no guarantee you'll like TES, because it does things differently than most other games. On the other hand, the games are pretty much designed to stand on their own, with the previous games taking the role of history (you can find references to the events and characters in dialogue and books). There are a few things you need to be prepared for in TES, though:
1. No XP. This one gets a lot of people. You get better at your skills by using them (or visiting a Trainer). You increase your level by increasing your skills a set number of times. Higher level enemies do not (at least in previous games) increase your skills any faster than lower ones. Personally, I love this system, because it makes perfect sense. Why should I ever be able to increase a skill without using it or being trained? A lot of people, however really hate it. IDK why.
2. Limited Structure. Another one that I personally like about the games, but others hate, is the lack of structure. It's entirely possible to put 200+ hrs into TES games without ever touching the main quest. The games are about as close to a true sandbox RPG as I've ever seen. The reason for this is the focus of the game is let you play the character you want to play, the way you want to play, doing the things you want to do.
The narrative and plot are there (multiple ones in fact since every faction has their own plotline), but they're only there as a framing device. The real meat of the game is giving the player a big open world and the freedom to do what they want in it.
3. More or less realistic.[/i] The game is grounded in realism, even though it's about elves and dragons, etc. What I mean is don't expect to be wielding a sword the size of a car anytime soon. And don't expect to be slaughtering groups of enemies with one swing. The focus of combat is on duels with 1-3 enemies. Those few enemies poses a true threat to you. You can't wade through endless waves, dragonborn or not.
What I really suggest doing is picking up Oblivion for cheap and trying it out to see if you like the overall approach of the series. Bearing in mind, of course, that Skyrim will be addressing a number of the annoyances from that game (enemy leveling, etc.).