One of the big things I like about virtualization is that you can find or build solutions that match the size of the problem you have. Need live workload migration? Buy VMotion. Need dynamic load balancing? Buy DRS. But if you only need to move your workloads around once in a while maybe you can get by with something like Mike DiPetrillo’s quick migration script. Cheap, easy, right-sized, and it has a well-known path for growth when you decide you really do need VMotion or DRS.
Which, by the way, is why I’ve been telling folks to skip VMware Server and go straight to the free ESXi. That way, when they decide that virtualization is cool and want more of it, all they need is some license keys, rather than a big conversion process.