Go for it. As long as it is available. I got off the last series here; since AMD has long stopped production. So I got it for a good price ("it is obsolete !"), too.
If I were a gamer, I couldn't recommend it, but everyone knows that Sempron is the cheapo-series of AMD anyway.
At around US$ 40 it is simply great. I bought a nice, cheapo, mainboard with it, similar price, and 512 MB of DDR400. Also around that number.
The three make a fantastic desktop; everything onboard (sorry, waiting for the product to become available for review on dooyoo !) and definitively fast and responsive enough for all kind of office applications.
Best of all: When you get the SD*A*2600, you have a full-fledged 64-bit system. I was sceptical, therefore I tried it with a 64-bit operating system, and it works great.
I see another advantage in this chip: the boxed fan has a larger diameter and therefore runs at lower speeds of below 3000 RPM. Mounting is easy, the heatsink compound is attached to the generous heatsink. Just plug the CPU, put the heatsink on top, turn the lever and you're done (don't forget to plug the fan into the mainboard, of course).
Minor inconvenience: the 2600+ is available as 754 socket, 939 and AM2 (940) socket. You need to make sure to get the proper one (this review is for the 754), and the suitable mainboard: for 754 ! (Those are the cheap ones) No, other mainboards are not compatible !
AMD Sempron processors for desktop and mobile products offer best in class performance, compatibility with all the applications you need, and the reliability of AMD processors.