What is your one stop shop to look for samples/loops free or paid (Sonar X3 friendly)?
Last night, I was playing with some loops provided by Sonar and final outcome was pretty good. 
I wish I had more loops to explore...
Too many choices on the web..
What criteria do you look for to find rich sounding loops?
Anything wrong with buy low priced loops in Ebay. Needless to say, everybody most likely want to end up with loops that sound rich, heavy!!
 
Thanks in advance. 
 

Loopmasters

This may sound like a copout but I can't think of a one stop shop for that sort of thing. I have taken advantages of offers from a sources as diverse as large scale sample providers like loopmasters, zero-g and big fish to independent guys looping clanking pots and pans. Not to mention good old-fashioned rolling your own. I think the closest to one stop shopping is going to forums like kvr that have dedicated sample sections with links to all kinds of free and paid sources.

Another tip is to check production forums for specific genres. They often have links to samples as well. Bedroom producers blog often has freebies of loops.

Resist the urge to simply string loops together because it becomes boring fast. Experiment. Chop the loop up. Rearrange. Mangle. Take chords and play new melodies from them.resample througb filters and reduced bit depth. Make it so the the loops mother would not recognize it :) It's fun and sometimes the source of new subgenres.

Digital Sound Factory
Producer Loops
Black Octopus Sound
Zero-G
 
whether it is a free loop / sample pack or a purchase I ALWAYS make sure to read the end user license and make sure the samples/ loops are royalty free and for use in commercial music.  You never know if you might want to use a sample in something and it goes pay. 
 
Many companies have Try Packs or small free packs of samples / loops.
 
Sample Logic has a try pack for using samples from their Kontakt library products. 
 
I NEVER buy sample packs or libraries of loops from Ebay.  you just don't know if they are cleared samples or some guy in his basement sampling records / stealing others samples.  too risky for me.

MachineClaw
Digital Sound Factory
Producer Loops
Black Octopus Sound
Zero-G
 
whether it is a free loop / sample pack or a purchase I ALWAYS make sure to read the end user license and make sure the samples/ loops are royalty free and for use in commercial music.  You never know if you might want to use a sample in something and it goes pay. 
 
Many companies have Try Packs or small free packs of samples / loops.
 
Sample Logic has a try pack for using samples from their Kontakt library products. 
 
I NEVER buy sample packs or libraries of loops from Ebay.  you just don't know if they are cleared samples or some guy in his basement sampling records / stealing others samples.  too risky for me.

Very good advice.  There have been a few prominent producers that have been sued over loops they thought were legal. 

Tuns free (and royalty free) stuff here....139 pages of samples...
 
http://www.musicradar.com/news/tech/free-music-samples-download-loops-hits-and-multis-217833
 
good luck

Big Fish Audio is another place to visit.

I like the Sample Magic Loops.  Cakewalk has some of their subsets available at the shop.  I find they are usually very high quality.
 
I would say that yes you have to be careful of the loops that you buy on Ebay, but I've made out pretty good by picking up some legit commercial loops that were produced on CD.  You do have to know what you are looking for.  Look specifically for these types of names:  Big Fish, Prosessions, Sample Magic and the Sony Audio Series stuff.  Since they are on CD or DVD, they are usually older (since newer ones are all download now) but you can breath new life into them by using them by cutting them up, layering them and even using them in additive, granular and as oscillator waveforms. 

I had a listen to The Loop Loft's offerings the other night and was so impressed I bought some. Very good. 
 
http://www.thelooploft.com/