Weighted keys make a world of difference if you're trying to play piano. They take a lot more pressure to push down, like a real piano, so you'll get a more realistic feel which, if you're a good pianist, will affect your sound.
You still haven't said anything about price, but since you don't really have pro-level skills, you're probably looking at one of the lower-end workstations. Each of the big three manufacturers (Roland, Korg, and Yamaha) have their big flagship workstations (read: expensive) and their scaled-down models that are much more suited towards people who don't have pro budgets to spend.
In that range, you're looking at the Korg M50, Roland Juno series, and Yamaha MO series. My personal preference is either for the M50 or MO; I can't really recommend the Juno series. In my opinion, the M50 is the better choice if you favour synthesized sounds, and the MO is the better choice for acoustic sounds.
If these are still out of your price range, one of the low-end Junos, the Yamaha MM series, or looking for something used (the Korg TR and Triton LE are both good and discontinued, recently in the case of the TR so Korg could introduce the M50).