You guys didn't read my comment on Chuck's blog I suppose. Oracle SE can go to 4 sockets, SE One goes to two. (I hadn't checked since I did my EE-SE migration but I just checked again now)
And Oracle SE is unlimited cores per socket, unlike EE which you pay based on the CPU ratio math stuff that Oracle has.
VMWare certainly can simplify setting up high availability with Oracle, though if your using Oracle I hope you have at least some expertise either in house or consultants.
Though VMware won't really help in scaling an Oracle SE instance beyond one system since that would need RAC.
The limitation of 4 sockets for a SE RAC with unlimited cores I think is fine even today, that's a MASSIVE amount of compute power for a DB, it could run circles around the $120k+ 8-way Itanium HPUX servers that I used a couple of jobs ago that ran Oracle(2005-2006), and that DB had 10s of TB of data in it). As with most databases the bottleneck is often I/O, not CPU. Having 16-24 cores today in a single schema with tens of gigs of memory is a steal compared to pricing of Oracle EE.
(4x6 core) 24 core Oracle EE w/RAC = $846k (list)
(4x6 core) 24 core Oracle SE w/RAC = $70k (list)
I would not use VMware myself if it was a highly loaded DB and your concerned about costs, just go bare metal and leave the VMWare licensing behind, don't forget if you want good MPIO in VMware, you need vSphere 4's highest end version which is $3500/socket, so that's an extra $14k, plus you need to throw in the cost of the 3rd party MPIO(don't know how much that costs yet). Spend what you save on EE on a good storage system, good servers, and good network connectivity. Also set some of that saved $ from EE aside for when 8 core CPUs come out, upgrade your system again.
MPIO prior to vSphere 4 isn't all that great, and if your serious about DB use your going to be using fiber attached(maybe FCoE if your feeling lucky..), not NAS or iSCSI.
There are more limitations to SE than just how many CPUs it will scale to, such as not supporting any of the other advanced HA features or scaling features of EE like partitioning and stuff. Also you can't perform online RMAN backups from a standby SE, and if you want a standby server you have to set it up by hand(copy logs, apply etc), it's not automatic like it can be in EE.
There are others as well, if your lucky it will be fairly easy to migrate to, my company at the time did not have to make any application level changes to support going from EE to SE. Also Oracle Enterprise manager isn't available for SE, even though you can install it, technically you can't get a license for it(doesn't stop it from working though).
Also note that if you downgrade to SE from EE Oracle won't let you "convert" your EE licenses(at least they didn't with us) you have to buy new ones.