Static, RIP, EIGRP, OSPF, BGP, IBGP, IS-IS and any other routing.
what are you using for DHCP? you will have to find out if that product supports any type of roundrobin type thing for giving out the default gateway.
in talking with the folks here that support our DHCP server it is not an option to load balance they just hand out the two address in the same order every time.
I am in ageement with your statement concerning load balancing. To achieve an 'even' load balance with 2 different gateways you would want an equal number of conversations to traverse each of the uplinks. However, if you cannot control which PC's receive each gateway address then you cannot load balance in an 'even' manner.
I am thinking that GLBP is the solution here, utilising just one virtual gateway address but multiple MAC addresses are returned to the different PC's for this address.