A-Z by all means - for ignos like me who know a lot of songs but usually have not the foggiest who they're sung by or what they're recorded on, album and artist lists are very frustrating. I wouldn't advise chord symbols - use the letters, and, if you feel it appropriate, include a list of the commoner symbols in your page.

Shall be very interested to see it [and you may well get more commissions coming your way!] Good luck