The difference with Graphics is obvious, as is Gameplay. The small roleplay elements are there, but not overly so, remember not even the old Fallout Games were pure Roleplaying Games either, they too were a mix of things, though Fallout 1+2 were alot more Statbased, you had to know what to make of your character to be any good, the same holds true in Fallout 3, although the difference is you can win basicly by using either VATS all the time or simply being a good Shooter (granted with low weaponskills you miss more often but you probably wont die due to that), the game is alot more action-oriented than its predecessors, sure you can also talk your way around a few encounters, but there is almost no way to avoid "random encounters" (unless you can spot enemies from a few meters away) or most of the fighting in general. So yes, if you want to have more Fun doing all the other crazy things you could before, pick Fallout 1 or 2, whichever your choice over Bethesda's Fallout 3, if you dont mind the whole action-part then you will probably enjoy it, all around its solid, but its still a hybrid of different ideas, just dont expect it to be the "best game evar".
Fallout 3 is Fallout alright, in the same way as Fallout Tactics is Fallout, imho it just doesnt deserve the number 3, i played it and found that, after completing all the mainquests and sidequests, i had little replay-value, since it was pointless to make another character since overall, the possible choices were limited. Sidequests are basicly either "Do" or "Dont Do", there were no choices in how you could accomplish them for example and most just required you to "kill this" or "find that". In Fallout 2 in comparison, aside from sidequests and the Mainstory you could have alot of fun doing just something else, if you were into that anyway.
Note that im not comparing it to Oblivion as i never played that game, but as someone before me said, its somewhat the same, just with Guns.
