A lot will depend on budget, opinions will vary wildly as to which machines are best, I've had all sorts said about my choice! My newb advice would be to have a good look around this forum, get to know people and to visit somewhere with lots of playable machines so that you can get a feel for your favourite.Played a lot of machines from the 90s, so would ideally be looking for a machine from that era, do you have any machines yourself, any recommendations?
As @Sharkbait says, your budget will dictate what you can realistically get. Cheaper machines tend to be the less popular, either for theme or their lesser gameplay, but one persons crap could be another's gold (just Google: popeye pinball grizz)Played a lot of machines from the 90s, so would ideally be looking for a machine from that era, do you have any machines yourself, any recommendations?