Your requirements didn't come out clearly yet. Choice of a microcontroller family is mostly a matter of previous experience and available tools and secondly of particular technical parameters. Your specification, as far as told, can be met by all major microcontroller vendors and a wide range of their chips, I think. You have also mentioned different programming methods, in-circuit programming by an external adapter (e.g. PICkit 2) and through UART using a built-in (either vendor supplied or user defined) bootloader.
I am totally getting confused
The problem is, that most microcontrollers on the market (except for some legacy types without ISP or bootloader option) met the criteria. In my personal choice, I have e.g. various PIC types, Atmel AVR, Philips and Analog 8051 variants, Renessas M16, TI MSP430, probably some more.
Your original question has been completely answered in my opinion, but now, you apparently want edaboard members to choose a microcontroller for you, but without knowing about the prerequisites. O.K., I opt for a PIC18. Microchip has a selection table for it. Or simply choose a type, that you can get in a DIY shop next door.