One post per topic plz
Your question is like asking for the best tool .... the answer kinda depends on what you are going to with it..... if you wanted to bang in a nail, take out a screw or tighten a bolt I would give you 3 different answers. the best would be the 4970k which is an i7 and is great for both gaming and mutlithreaded applications. The 4690k is an i5 and is fine for gaming.
Both are under 300 pounds
http://www.scan.co.uk/products/intel-core-i7-4790k-s1150-haswell-4-core-44ghz-turbo-5-gt-s-dmi-12ghz-gpu-40x-ratio-84w-retail-c0-st
The 3770k is still a viable processor but it's 3rd generation back. Makes no sense to buy one today.
Devils Canyon (4790k)
Haswell (4770k)
Ivy Bridge (3770k)
Sandy Bridge (2700k)