Outer Vegas - Something about it... I dont know why but I loved it. And coming across the occasional fiend was also really cool. I just wish they had some more quests and locations out there. And maybe some more friendly NPC's as finding fiends around every corner gets boring after a while. This would be the one place I would like to have a house if I could have one since it is nice and quiet and I could place some plasma mines around and sleep safe and sound.
Freeside - cool atmosphere and everyone likes it. Has some good shops and I wouldnt mind being here for a while. Also it is cool to see those kids chase their rats around and see the occasional thug try to challenge me but finds it difficult when my companion shreads him apart.
The Strip - cool atmosphere I just wish the Lucky 38 was open for gambling and it would also be cooler if every so often some Legion Soldiers would attack the strip and war breaks out over the strip between the NCR/Securitrons vs the Legion and have the NCR win and things go back to normal.
Gomorrah, Lucky 38, The Fort (Big fan of Roman History) and a lot of other places. For some reason I really liked Sloan I guess it was kind of nostalgic of a typical FO3 settlement.
After reading the comic that came with the CE version. I loved that I have found two areas that are represented in the comic. Chances map and his grave.
I would put spoilers around that but I have no clue how to.
The story behind Vault 11 was kinda "No way.. Oh.. Ohhh that svcks!" at the end (I meant for the people who did the sacrificing.) I mean you kinda knew but also thought it was too easy. Plus I like the way they introduce the end in the beginning.
On another note I liked the way the camera tinted in Searchlight and at Legion encampments