My favourite is the A340, it reminds me of the 707 and DC8 - classic airliners!
I've been doing a fair bit of over water traveling in A340s over the past couple of years, and I agree they're nice looking. Also that having four engines appeals to me in that over water role. That said, I was once in a 757 that had an engine failure on takeoff (bird ingestion) and it appeared to be almost a non-issue from the cabin. I'm glad it was only one...
A airline pilot friend who stuck with flying DC9s as long as he could, has recently been forced to move to A319s. He says its still not a bad job as jobs go, but retirement is looking better...
The Pitts S1S is maybe the most esthetically inspiring plane to me, but it has to do with everything being absolutely minimized in size... something like a 1960s cigar shaped racing car.
The SF260 is wonderful too, but in a more expansive way - like a 1960s Ferrari.
That Schleicher KA6E glider is undeniably lovely.