Merry Christmas and Happy New Year!
I myself do not use any simple PIC programmers without a PIC as the brain of the programmer. Still some people think PICkit 2 is too expensive at US$35. So there is still a market for the simple programmers. Coupled with bootloader, it can still be useful for some hobbyists. Of course I will still recommend PICkit 2 to those who can afford the US$35, it is well worth the money and save you a lot of troubles with the simple programmers.
Windows simple PIC programmer software sites often links to the supported hardware. Some of them are based on Parallel port (eg: Tait), some of them are based on Serial port (eg: JDM), very few of them are based on USB. Parallel port and serial port start to disappear from many laptop computers. And many of the serial port based programmers will not work properly with common USB-to-Serial converters. Almost all Parallel port based programmers will not work with common USB-to-Parallel converter (often made for old printer). Some of the very simple programs only support LVP (low voltage programming) which only applies to very few PICs (but some of the PICs are popular). So far I can see that most simple programmers do not support 3V only PICs like PIC18J/18K and PIC24/dsPIC33 which PICkit 2 support well.
WinPIC supports many 5V PICs and its manual seems to be quite good. Another advantage is that the author also provides the source packages.
It claims the support of most Flash PICs and can rival some of the features of PICkit 2. But take note that its main supported programmer GTP-USB+ is actually an intelligent PIC programmer and at 60 Euro it is much more expensive than PICkit 2 which costs US$35 . If you are using the simple programmer, I am not so sure if it still supports the same number of device.
PICPGM also supports quite some PICs. One interesting thing is that it has an FT245BL based USB programmer which unfortunately only supports LVP.
IC-Prog is perhaps one of the most popular programing software in the web. However, its support of PICs is actually one of the weakest from the website.
pikdev supports many simple programmers and PICs under Linux.
piklab supports many simple programmers and PICs under Linux. Of course, it also supports many other programmers, including Microchip MPLAB ICD2.
This is different from the maybe-better-known picprg (http://www.brianlane.com/software/picprg) but it is actually much better than that one.
It only supports Parallel port based programmer. But anyway, parallel-port based simple programmers is said to be more reliable than serial port based simple programmers.