I started out with Abyss because it was free. It's kind of slow and the more complex my PHP scripts became the more likely it was to crap out on me.
// but then again, it could have been the sloppy code writing of a beginner
If your using Windoze at home you may consider WindowsXP Professional which comes equipped with the IIS server. You'd have to download and configure the latest version of PHP:
PHP.NET
and to unlock the real power of PHP:
MySQL
The WROX PHP Beginners book I had then had the instructions on setting up both with the IIS server. I'm not sure of a web based alternative that makes it as easy as the book I had.
I have used my Windows box to create and test my PHP applications, and there was no noticeable difference in how they performed once uploaded the TCH servers.
Frankly, I think running a server locally is imperative if you're going to go much farther than simple scripts.