You won't generally get any noticable problems with different speeds of RAM; but it will only operate at the slowest speed. I would recommend the first one because its cheaper, and all the others will work at the same speed anyway. Unless one day you plan to upgrade the old stick and buy a new PC3200 or even PC3500. If you may do that then it would be advisable to get the level you plan to upgrade to at a later date so that you don't have to replace both sticks to get the desired speed.
A Knight is sworn to Honour. His heart knows only Virtue. His blade defends the helpless. His might upholds the Weak. His word speaks only truth. His wrath undoes the Wicked.