Budget allocation for site launch - advice needed!

I can't speak for the EU Market but certainly if you're looking to attract UK recruiters there are a few directories you need to make sure you're listed in. Some are free and some will cost you a few hundred pounds depending on how fancy you make your listing.  Try Onrec, UK Recruiter, whatjobsite, Ri5 and Whatmedia.  Onrec offer a press release service - they send out daily email alerts to their database of recruiters (and competitors!) so make sure you send them a press release about your launch.  If you've done any research and can offer some kind of industry insight and present yourself as an expert, this will also make for good PR so make sure you send info to all of the above, plus all the general HR magazines.

This probably goes without saying but you also need to make sure you’re hooked into job board multi-posters like Broadbean or Conkers -  find out which ones are most prevalent in your market area. If you're not hooked up you'll put off a lot of recruiters before you event start, no matter how great the functionality of your site is!

At the end of the day, the most important thing for the recruiters is your traffic and your applications per vacancy ratio. Therefore this is one instance where I wouldn't recommend spending lots of cash on paid search - save the money for attracting candidates to your site to apply for jobs, not clients to use it.  To get your clients hit the phones and 'be seen' in the online recruitment community.  If you can show potential clients that you have a robust candidate attraction marketing plan and posting jobs on your site won’t be too time consuming, it should be an easier sell.

Good luck!