I found using FS2000 to be of use during the navigation phase of the ppl if only as a confidence builder. It was reassuring to put in the wind speeds and direction, do the calculations and timings, then fly the route in the virtual world before doing it the next day for real. Any errors made on the computer were not reproduced in the aircraft.
There are limited visual references on the pc, but it can be argued that this stops the tendancy to feature crawl. It is also useful for understanding the practical use of vhf navigation and for developing a scan pattern.
I would recommend buying a control yoke rather than a joystick. Also, if you intend to continue beyond the ppl syllabus, then you may consider the Jeppesen FlitePro or the Elite IFR training simulators.
The only downfall of pc simulators may be that they are harder to fly than the real thing and that this may tend to make you feel you lack handling skills. This is due to the limited field of view and the lack of a `seat of the pants` feel for what the aircraft is doing.
Finally, they serve a very good purpose insofar as feeding your desire to fly even when you can`t afford to, or the weather prevents you. As long as you view it as a training aid and don`t get too `anorak` about them, pc simulators are great and plenty of pilots use them. (which is why pilot`s supply companies sell them!)