The Optigold ISP product is going to be redeveloped from scratch, while I'm not particularly looking forward to it, it will let me drop a lot of the legacy stuff, and have better support for things that were not as prevalent when Optigold was first released (broadband, web hosting, usage based billing, etc.)
So what I'm looking for is some input from Optigold users on the general direction of it.
Here are a couple options at this point:
FileMaker Pro 7
It's out now, and does some really nice things. The web server is built into FileMaker Server and the web server is truly multi-threaded. Another nice thing about it is 100% of the Optigold ISP client can be web-enabled without needing to redo anything (basically you can move through Optigold on the web, and it looks exactly like it does in the client). SQL, XML, etc. is also handles by the database server (as it should). It's MUCH faster than FileMaker 5.x/6.0. Allows you to do some other things I always wished FileMaker could do (for example, multiple windows with a unique found set per window... you could have have multiple windows on the Customer Info screen, each with a unique found set).
MySQL + PHP
This is another option I'm looking at. There really is nothing faster than MySQL for a database engine (think about generating 100,000 invoices in a minute). It's also free, and runs on any platform. The drawback to it is it would be 100% web based, so there may be a couple minor things that are not longer possible.
My vote is for the PHP / MySQL option. This is, as clients go, the most platform independent solution to my knowledge. Filemaker is great, but too many times we heard that Filemaker was the limiting factor.
Don't get me wrong, I love the product, but I think it could go much further in that direction.