For a Nikon D90 and light-to-moderate lens setup, a mid-range tripod from a reputable brand should work well for years. Based on the answers, Manfrotto and Slik are solid options to consider.

For outdoor travel use, balance stability against portability. A heavier tripod is generally more stable in wind, and a center hook is useful because you can hang a bag from it for extra weight. But if the tripod is too large or heavy, you may be less likely to bring it with you.

A commonly recommended fit in your budget is the Manfrotto 190XPROB: it’s not excessively big, not too flimsy, and is suitable for enthusiast use. The general takeaway is to avoid going too small and flimsy for outdoor shooting, but also avoid buying something so heavy that it stays at home.

In short: look at mid-range Manfrotto or Slik models, prioritize stability, manageable carry weight, and features like a hook for added ballast.