First check http://mxtoolbox.com

So not to forget,

Host Record Priority Mail Server
@ 1 ASPMX.L.GOOGLE.COM.
@ 5 ALT1.ASPMX.L.GOOGLE.COM.
@ 5 ALT2.ASPMX.L.GOOGLE.COM.
@ 10 ASPMX2.GOOGLEMAIL.COM.
@ 10 ASPMX3.GOOGLEMAIL.COM.