PBX Server and SIP Phones

Has anyone setup their very own PBX server and SIP enabled phones to make their own phone system?

If so what software did you use/recommend ie trixbox, elastixbox, etc

What phones did you use/recommend? polycom,etc

What providers did you use? Costs?

i have built quite a few if costs are not an issue i would suggest looking into five9 its contains all you need and is one of the most robust systems i have used however the 170 a month seat cost is hefty. i am building a asterisks pbx so i can create ivrs, they have a windows version as well that is solid askteriskwin32. Sip phone and accounts you can get free if you don't need more then a few.