The Falcon 2000 or the Global Express.
You can get plenty of work with a G4 rating but the rates have been coming down to around the same rates for the F2000 ($450-$650 a day). With the excess of pilots and the overall number of G4's (coming up on 500 aircraft) out there, it's competitive to say the least. Most of the people I know have no problem finding a qualified G4 pilot. The only pilots I know that are flying with no experience are the ones that just purchased their types and they are working for far less then scale rates. The F2000 rating costs less and will get you the same amount of work as a G4 rating.
The G5 rating will get you work and a much better day rate but the big difference between the G5($800-$1000) and the Global, is NetJets.
Netjet pilots are on a 2 week on 2 week off cycle. The Netjet pilot who wants to work during his 2 weeks off, has no problem doing so. I know of one pilot in particular who works an additional 3-4 days a month(during one of his 2 week off cycles). That's an additional $36-48k on top of his G5 NetJets salery. He still winds up with 10-11 days off at home.
Their are no Global's at NetJets and subsequently their are fewer pilots available and the day rates are higher ($1000-$1200). The big BUT is, their are fewer Globals out their.
The type rating costs the same as a G5 but before you spend the $35k I would line up some potential clients (that goes for for any type that you purchase).
Most folks hire a temp pilot as a relief pilot on long haul international or because someone is out on vac or ill. They want an intl qualified pilot because they have a long haul aircraft. If you are not an intl guy, go with the F2000, it doesn't require the intl experience. It's not something they can hold against you. Besides it's a great aircraft to fly.