Newbie needs help

I am ready for my first HTS and have some questions I hope someone can answer for me:

1. I was told by a seller/installer that it was OK for the 3 front speakers (bookshelf)to be close to each other. I only have anout 4.5 ft to work with. Is this ok?

2.Are in wall speakers inferior to bookshelf speakers?

3.What about satellite speakers as compared to bookshelf speakers?

I have a large open room where wiring speakers will be difficult to say the least. The accoustics in the room are not good so I don't expect fantastic results.I will spend around $2000 for speakers and receiver.

Any help you guys can give me would be much appreciated.

Thanks