Intel's tend to be faster but they are some of the priciest. Personally I'd recommend the Vertex SSDs by OCZ. I'll be buying one soon, and a friend of mine got one recently (a 60GB Vertex II) and lovs it.
As for your other question I direct you to this news source:
Intel's 34nm-based 320GB solid state drive creeps closer to reality
While there is no date stated, there are larger Intel ones coming out soon.
And for the record, currently the highest capacity SSDs are at 512GB.
In case you hadn't guessed, I've been keeping a track of SSD developments and prices for a while now