I might start with my worst dip as it seems easier! That would be Peregrine. I've seen plenty during the year but they are all the 'usual' resident birds. I just didn't manage to bump in to one unexpectedly while out birding. That said, this year I've done a lot more birding in the Ivel Valley which does poorly for Peregrines generally so perhaps not that surprising.
Now on to the good stuff! 'Best find' is a bit personal. If you're talking rarest then it has to go to the Great Skua which flew over Richard and I as we were off to Broggy to see Barry Nightingales bird. It being a county tick for both of us too made it quite special. However from my perspective it wasn't that memorable as I really only got views of it flying away from me as I was driving as it flew over the car and I was trying desperately not to drive in to the Ivel!
The two Lap Bunts should also get a mention in here, but I only really saw then as silhouettes as they went over calling. A bit unsatisfactory, and there weren't even a find tick, unlike the Skua!
Below the rarest there is a selection of birds which I really love seeing, and finding them locally is even better. These included the juv Caspian Gull at Broom which stayed around for a couple of days and enabled a few other birders to catch up with it. A tricky plumage to id a Caspo in so that was very satisfying to pull of of the Broom roost towards the end of the summer.
Another 'species' I've had a little crush on this past year or so is Siberian Chiffchaffs. Wintering Chiffs in general are probably under recorded and these colder looking birds are probably further still under recorded amongst them. Since October 2013 I've found at least four of these birds locally but each of them have been interesting in their own right. It's clear there is much still to uncover about these birds and there is opportunity for everyone to contribute to our understanding. So if you see a chif in winter, just take a second look at it, just in case.
I have four other species on my list: Ring Ouzel, Firecrest, Tree Sarrow, and Hawfinch. All these provided a good dose of enjoyment or surprise for different reasons. Two of them were satisfying as I found them while actually looking for them: Firecrest at The Lodge and Tree Sparrow at Upper Caldecote. The other two were complete surprises as they flew over. The Rozel went over chuckling with a load of Fieldfares while Darren and I were looking for the Lap Bunts at Warden Hill, and the Hawfinch went over as I was crossing the car park at The Lodge on my way for a pee! It pays to keep your ears open.