The 16F684 is fine for now. It all depends on what you need to do. More I/Os, memory, built in hardware? But for learning the small ones are good.

I am a big fan of the PicKit2 so if you can get one at a good price do so. But for now the PicKit1 is fine for the parts you are using. It is just very limited parts wise.

What do you have in mind to do with all of this? Home automation/monitoring?

There is so much that can be done with the "small" parts and they can be made to share information they may be all you need.