My TEC180FL would have to be my favourite. Its a versatile instrument, large aperture for an APO yet still "portable". Views are very good and for imaging it'll do both widefield and the larger galaxies.
AP140 would be my 2nd choice. Unbelievably sharp views visually. Even though I'd had several excellent scopes, visually it took me by surprise at how pinpoint stars can look.
12 inch newtonian at the Melbourne observatory, dont know if the seeing on the night was excellent but that scope imprinted something that says this is what planetary visual should look like.
almost left it out C14. Good all rounder. Minus the norrow field.
Toss-up.
AP155 or IM815D
The AP gave spectacular star fields, the 815 spectacular lunar and planetary & DSOs.
Mind you, if I could have gotten my 12" dob to stop shaking and twirling.....
Of all the scopes I've owned or currently own (10" LX200R/C11/AP130GT/SV90TBV/ETX90) I would say my C11 - a nice compromise for visual/portability and a solid performer for planetary imaging.
On my 4th scope, and it is my favourite so far: CGEM 925. HOWEVER... there are negatives to it (cooling time, lack of aperture) so I think my real favourite is yet to come!!
I must say it isn't the top shelf of scopes but i do like my 127ED meade knockoff, then the ED80 still yet to really use my C11 and meade 14". I can always dream of a TOA 150.....
