Upload & Sell: Off
The Apollo has become more useful now that Canon has radio controlled flashes (because the flash is buried within the softbox), and the second notable aspect is that it is easier to gang up two or more speedlites in one box (vs. from behind a softbox or beauty dish). That being said, the radio controlled flashes are very expensive, and they are Canon, not Nikon...so far. I bought a cheap Apollo eBay knock off that comes with a grid. Seems adequate to me. Those knock off's are cheap enough that they need not be a deciding factor in where you go. The issue is the strobe.
I agree with Chuck that the Alien Bees are the best bang for the buck, but maybe not the deutsche mark/euro? I hear they are pretty expensive over there. Maybe a used one off eBay would be the way to go. That's what I did.
The next question is remote triggering. If you're really on a budget, use the optical slave. If you do get Buff's remote triggers, definitely get the CSR+ (or CSRB+ if you go outside the studio), because eventually you'll want to graduate up to the Cybercommander and potentially the Einstein level of strobes. The CSR+ module is not much more than the CSR one. I don't know how compatible it all is with European plugs etc.; could be just fine, though.
One other fun fact that is often brought up is that Annie Leibovitz often is found using the "Softlighter II" umbrella softbox by Photek. That's simple, cheap, and portable. If it works for her.... There may be improved versions out there, and what I think you need to look for in the newer types is one that comes with a grid, so you have more ways to customize the light. The Chinese knockoffs now often come with a grid, which is new for the last year I believe.
Used to be hard to get gridded softboxes without paying big bucks. In fact, the grids used to cost more than the entire softboxes, including that Softlighter II, which to my knowledge can't be gridded.
The other very cost effecient and weight efficient accessory is a reflector, which you may already have. The collapsible ones are widely available. With one or two lights and a reflector, much can be done. I just last night ordered a white foamcore board from B+H. I've seen great results from something like that and just one AB strobe:
Joel Grimes (in that video) uses Buff gear. Nice thing about buying a used Alien Bee is you can sell it for not much less than you pay for it. Their value holds very nicely through the years.