handcoater,
Another vote for a 4x5 enlarger, rather than anything smaller. More robust and rigid, and flexibility in case you later feel limited by medium format.
Omega D's and Besler 45 units would likely be front runners due to availability in the USA. Along the same vein, parts and accessories for them will likely be available, long after the smaller units make their way to the second hand shops, dump, etc. Currently they are going cheap, and you might be able to get what you need for little more than just for showing up with something to haul it all away.
Durst are great units (and I understand so are Deveres), but parts may be a problem (availability and expense)...
To give you an idea where I put my money, currently own a D5 with dicro head (and condenser head in a box), and a Durst L184 8x10 with a condenser head I am setting up. But then again, I do shoot both 4x5 and 8x10...
Hope that helps,
Len