Just completed this today at level 17, pretty epic game. Playtime for me was just under 30hrs, but to be honest I only really got stuck into the main story during the final 10hrs of playtime (when I got to Rivet City). One thing I found is that the game leads you down an accelerated path towards the end, with fewer (obvious) sidemissions to distract you. I suddenly realised that I'd reached pretty much the end of the game which was a little disappointing as I was expecting to get sent off to more locations up north or something. Might have to reload my save and go adventuring.
Interestingly I found ammo rather scarce during the first half of the game, then once I got a few extra weapons it was no problem at all and by the end I had stacks of stockpiled gear. Once you start fighting the enclave you get loads of energy weapons etc
Lockpicking took me ages to get the hang of, at first I was failing very easy ones all over the place. I didn't realise all you need to do was roll it either left or right, I thought you had to use all the directions!
Overall a very good game with a definite nod in the direction of Deus Ex, both in terms of the gameplay mechanics and the endgame choices. In fact I would say that this is arguably the true spiritual successor to Deus Ex. The scale is truly impressive and there's quite a wide tree of dialogue branches to go down with some characters.
Is the DLC worth getting? Bearing in mind I suspect there's dozens of quests I've not found yet in the main game.
Might have to give Oblivion another go I suppose, I found I couldn't really get into it