Well, Kirk Hammett said in an interview that 90% of what he plays with metallica is rhythm , actualy live James do more interaction with fans than playing guitar ... I believe they got hidden guitar assistants for live stuff too.
Anyway all of the lead guitarists I know play rhythm ... Dimebag , Petrucci , Gilbert , Friedman , Slash , Page ,Hendrix ,SRV , Vai , Satch , Hammett ... Just to name a few.
On the other hand , most rhythm guitarists can't play good leads or can't execute some special techniques (specilay with fast bpm)... No offence to rhythm guitarists , most of my friends play rhythm, and I never try to discourage or show off against them , unless someone start showing off...
About B.B. King can't play rhythm thing ... What rhythm do you mean? do you mean he can't play like Hetfield ?
If so, there is no comparison from this point... You can't compare Van Halen to Andres Segovia, Megadeth to Gipsy Kings, etc. ... These are 2 different styles.
I haven't heard a lot of B.B. , but I remember that there ain't any guitar rhythm in his music , just bass & drums , right? You can't judge his rhythm playing unless you hear it.
But a comparison between Hammett's & Hetfield's technique is possible , they both play same style of music, and they both played rhythm & solos. If you compared their rhythm playing they draw , if you compared the solos , for sure Hammett wins.
And as I said in a previous post, you can't separate between Lead & Rhythm anyway.
Of course you dudes know I'm not offending anybody ... Just trying to explain my point, that Hetfield's rhythm playing isn't better than Hammett's , but his songwriting certainly is...
And that I'm against the separation between lead & rhythm in the same music style.
If you don't like my points , just forget about it and lets close this thread... Such discussions ain't realy usefull and won't add or subtract anything . :)