Well, I voted for St. Theodulph, so you don't need to go back, Azizi. ;-)

I think there are little links to the midi files somewhere in the blog.

And yes, "Our God, our help in ages past" is the same song and to the same tune (St. Anne) as "O God, our help..." Isaac Watts, who was after all a rather particular Puritan, wrote it as "Our God" and a generation later the more broadminded, less parochial Wesley brothers rewrote the first word as "O". Since St. Anne was composed in 1708, it may well have been the tune of choice for the text from the very beginning.

Other texts the CyberHymnal lists as sung to St. Anne are
   1. HAIL FA­THER, SON AND SPIR­IT GREAT
   2. O LORD AND MAS­TER OF US ALL
   3. LORD, AS TO THY DEAR CROSS WE FLEE
   4. LORD WHO HAS RE­MEM­BERED US, THE
   5. LOVERS OF PLEA­SURE MORE THAN GOD
   6. O GOD, OUR WORDS CAN­NOT EX­PRESS
   7. O GOD, THE HELP OF ALL THY SAINTS
   8. O GOD, THE STRENGTH OF THOSE WHO WAR
and there are certainly others, including newer ones not in the CyberHymnal for copyright reasons, such as "Creator God, Creating Still". Here is a simple MIDI of St. Anne.

And here is a similar MIDI of St. Theodulph. Its customary text is "All Glory, Laud and Honour" (a translation of the Latin hymn "Gloria Laus et Honor" written by none other than St. Theodulph hymnself); the only other text I recall seeing set to it in a hymnal is "Blessed be the King whose coming is in the name of God" (a fairly recent translation of a fairly recent Spanish hymn starting "Bendito el Rey que viene...") but there are probably others.

Haruo