We have just purchased a point to point connection between our 2 Data centers and wondered what is the best choice of VPN for this king of connection and also would we be best using ASA or Routers as endpoints.??
Use whatever VPN supported by your equipment (you didn't mentioned equipment you have) fulfilling your requirements (you mentioned no requirements).
if its just IPSEC tunneling you are after, you can use 4400 series. with the correct feature set.