I thought of this topic upon reading dubord's congrats thread and want to hear from everyone.
1. Your favorite cache.
2. Hardest or most clever cache.
I'm not sure I've done enough yet to post an opinion yet but so far my favorite cache was Mapachi's cache in the Vaughn Woods. I loved the Woods and had no idea they were there until caching. This one was so satisfying to finally find as it was well cammoed and I searched and searched and lost sunglasses and pathtags and then found both and finally found the cache on the way out.
Most clever cache for me was 18392 by Circles in Bath. I laughed out loud when I finally figured this one out.