As an old-time TTD fan who played even the original Transport Tycoon, I want to see OpenTTD take off in a big way. It's returned one of my favourite games to me, but a bit better polished and I don't need to play with my AUTOEXEC.BAT to use it any more.
First played TTD on a 386DX-25Mhz with 4MB RAM. Was still using TTD up until a few years ago when I got tired of having to install DOS packet drivers under Windows 98 to run it properly (at that point I wasn't even aware of the DirectX version and every copy I've ever bought, even those bought recently, has been the original DOS version).
OpenTTD has changed my setup from a 386DX-25Mhz with 4MB RAM, DOS 5, a 10Mbps ISA 10Base2 network card and more packet drivers than I care to mention to a 1GHz Windows-based, TCP/IP, Internet-play-capable, DirectX boosted version that's true to the original.
I don't do programming any more but I have sent in the odd tiny patch (show max loan in finance window etc.) and I'm quite familiar with the source to OpenTTD and I must say that seeing it come along as fast as it is can only be a boon for Open Source development.
My current patches (accepted into OpenTTD or not) are available from [My Website]. You can also find a list of my suggestions for the game there, as well as screenshots of the impact of my patches.