So, I beat the game and got all the achievements last week, I also beat all the DLCs and need a new challenge!!!

I'm level 50, so I need a hard one. (Or just anyone that you found cool or interesting!!)

What mods do you recomend,

Show me what you got!!!

Well, my mod GGE adds in a lot of new gangs and encounters: http://newvegas.nexusmods.com/mods/42840
It adds a bit of difficulty so if you want challenge you could try it out.
Though I've heard reports that using it with IWS can make for even more challenging encounters.