I am biased because I am very particular about what I like and don't like in video games. But having said that ...
Elder Scrolls - I actually got bored because it was -so- open that i kept going off in odd directions before realizing that the next 'best' place to go at that time is 'the other way.' BUT at the same time, when I was playing this game, I was on a small-ish tv so using the journal or reading too much dialogue, etc was more headache to read than it was worth. BUT, if you'll have a guide, well, then you'll know where you're going and won't get lost in the world. I eventually got too frustrated and stopped playing after a a couple days of playing. But what I did play was nice graphically and seemed to be a well developed world, etc.
Final Fantasy XIII -- I haven't played, mostly because i got tired of the final fantasy series a while ago (there were some choices earlier in the series that just left me unhappy so i never really returned to the series after that). having said that, it looks like a well-done game. it's a jrpg and it's final fantasy so expect a tight story line and really nice cutscenes.
dragon age: i really enjoy it the world they made. and the focus really is on choices (which i like in rpgs) and i like the way some minor things here and there change based on the choices, and with the different chapter 1 stories, you get to see various events from diferent perspectives (i.e. you play through as an elf and some villians have certain ties to your background so you know how and why they did some things whereas if you play as a human, you meet those same villains but you know and understand the backstory of different villians.). on the flip side, -i- would actually not want a strategy guide for this game because a) it is straight forward enough that you don't feel you'll get lost and b) it might ruin some of the nice surprises because the big appeal here is the chance to see the effects of your choices.
Any of these are old enough that you should be able to get used without too much trouble. Though word of caution, dragon age when new lets you download some extra content, you don't get that on a used version since the prior person may have used the download key. the other two should be just as good used as new (presuming they aren't scratched etc etc).