My preferred variation  

Karel? (...) Insofar as my own games are concerned, answering with or something hasn't often given satisfactory results; after that, white will play a pincer on the lone black stone instead with that wall of his. After that, when black tries to escape, white will be able to build an impressive wall for the right side.

My preferred variation  

That's the most peaceful option, and I rather like it - black gets the corner, white only has minor power towards the bottom, and the black group on the side where white has the wall is fairly safe, and it can be connected to the corner at b anyway - and there's the aji of the cutting point at a left to boot. I guess pros wouldn't play like this, but for amateurs (and those like me who dislike playing against gigantic moyos and walls) it could be okay.