Fallout: New Vegas Ultimate Edition

Obsidian just knows how to develop awesome RPGs.

It's a wonderful game, with deep meaningful choices, interesting characters and great role playing options, especially with the use of the perks in dialogue (ie black widow, femme fatale), the gunplay is a bit off, and sometimes the game slows a bit in some fights, but this is easily looked over if you like solid RPG experiences

It doesn't matter if you are looking for a truly worthy successor of original Fallouts or just a great RPG, in either case look no further. Out of the (proverbial) box you get one of the best storylines ever written by Obsidian, tight enough to keep you focused on it, yet giving you enough space for roleplaying whatever character you want, not many companies can do that right. World building is great, in-game Mojave feels like an actual, living, place, not just a framework for quests. NPCs, their dialogs and backstories, are well-written. DLCs are a mixed lot, but I wouldn't rate any as bad. Overall they all fell quite unique and are, at the very least, enjoyable. Game engine is a mixed blessing - Gamebryo is unstable in a strange ways that seem to be related more to black magic and twisted dreams of Great Old Ones than anything technology-related. It is also lacking in optimization department. Fortunately it is also as modder-friendly as it gets. Fallout New Vegas is infamous for the sheer amount and variety of mods made for it. Some fix it's shortcomings (quite aged graphics, fps mechanics or rather the lack of thereof, bullet-spongy combat, stability issues, basically if anything in game annoys you there is more than likely a mod for it), others add new content. Some quest mods boast DLC-quality and are definitely worth a try. Overall, Fallout New Vegas is not only a great RPG, it's an absolutely brilliant vortex of immersion, captivating story and sheer fun. With mods it's easily one of the best RPGs ever made, without them, well, it's still one of the best RPGs ever made, worth every dollar, euro or whatever other currency you've paid for it. Too bad it's more than likely last Fallout of it's kind.

Most replayability out of all the new fallout games (after 1 & 2)

In my opinion this is the best Fallout game or just game in general. The Story, Narrative, Atmosphere etc. everything is near perfect. And by good has the game good DLC´s. I love all of them.