This seems as good a place as any.
I am about to mod my xbox for the first time. I have Xecuter 2.6 CE ship...I am not sure what version of xbox i have yet since it hasn't been rippied open. Hoping to have everything ready first.
Question is to what bios should I use? There are so many...I am afraid of choosing the wrong one.
I currently have a modded xbox that was done for me about 2 years ago. It has the Xecuter2 lite chip...not sure what bios. Is there a way to tell? I am hoping to get all the same functionality out of my new one as I do with the old. I can currently Backup/play games, FTP,watch Divx and use homebrew/emus.
Any advice for a first timer?

Most all recent bios, have the same functionality as it comes to those things you have mentioned. The main difference between the bios in my mind is possible customization issues such as the boot screen and such... That said I would pretty much say that the X25035 bios is probably the most used bios for such a chip as you have. So I'd go with that one... I have 2 xboxs running that bios and they don't give me any issues. Also, when you download the bios file you will download two files, make sure you use the one that is compatible with your xbox... like you said, you don't know the version number of your xbox yet but you will want to know this... one bios file will be good for any version from 1.0-1.5 while the other is specifically made for a 1.6