I read Cell when it came out and thought that it was a good addition to King's works. I also agree with wyndhy that all of his stories are intertwined, all part of a larger King universe. He alludes to - sometimes not-so-subtly - this fact in the Dark Tower. All of the stories work as standalone, but put them all together and you get something much more magnificent.

That being said, I'm in the same case as Lil as to Lisey's Story. I got it when it first came out, but I just couldn't get into it. Maybe I'll try again soon.

__________________
I see your fantasy... you want to make it a reality

Are you in the mood to be subdued

You see these shackles
Baby I’m your slave
I’ll let you whip me if I misbehave

Tie me to the bedpost

I like it rough
cause I'd rather feel pain than nothing at all