IMHO, i think considering it's your first Patek, you shouldn't think of getting a 2nd hand, or from a grey mkt dealer. Maybe it's just me, but i have and am a firm believer that you should buy from an authorizd dealer (no matter how ruthless/bas****s they can get!). That said, 30k wouldn't get you far buying a patek, but it also dosen't mean it won't get you anywhere!
i guess it's really up to you, find out which Patek suits you best? If you have to do loads of black tie events, maybe something more classy, a calatrava? but if you've got a job which is quite in the sun/hard hitting, a nautilus? a banker or someone who has to liason with international markets? a world timer no doubt. but what i can say is wearing a patek to work when you boss is just wearing an omega isn't something i recommend! :P
Well, considering it's a first patek, you should really cherish it, think carefully of what you want? it's really a milestone in my opinion! something like once you get it, you'd forever look back and not regret! you want the first one to be perfect! don't be too 'miser' or 'cheap' yet regret later on!
all said, i wish you the best, and really hope you let us know what you settle for!