Who hasn't. I include some sort of hello to each check in that I make:

"xyz center, citation 1234, with you FL310" or
"xyz center, citation 1234, out of 270 for FL390, hello" or
"xyz center, citation 1234, FL370, good afternoon".

Why? So that the controller knows that I'm a new arrival (as opposed to making a vacating altitude call. It adds maybe an extra second (if they are so busy that I can't check in, then I don't bother anyways), and helps them sort things out quickly without having to look at the strips (I know because I've done it).

Additionally, I acknowledge squawks - at least with a callsign or a readback of the code. This way the controller can move on to the next aircraft instruction, without having to wait and see that you put the correct code into the box. If you don't acknowledge, then the controller has to wait until he/she sees it change on the scope, which might be as much as 5-10 seconds later (depending on the radar sweep and how quickly you input the code.)

My biggest pet peeve? The people that can't take a friggin moment to LISTEN TO THE FREQUENCY after switching over. How many times a day do you hear some dummy hit the switch to change freqs, then key the mic, stepping on a conversation or butting between and instruction and readback?