Welcome to the hobby!
There are several well priced 10 inch dobsonian mounted reflectors in the classified area...
A 10 inch dobsonian mounted reflector could easily last a lifetime...and would be great for visual astronomy...not so great for astrophotography but not impossible either. If astrophotography is where your real interest lies then I would suggest other types of scopes/mounts instead of a dobsonian mounted reflector.
I'd sure encourage you to try to check out a few scopes at a nearby astro club or a friendly IIS neighbor before you spend your hard earned money.
Once you get a chance to see a few different scopes in the flesh then I think you will have a better understanding of the type you should eventually buy.
With respect to different eyepieces and other gear, and your question about if the high end gear is worth it or not is a real subjective question...Is there a difference between the low, middle and high end in terms of expense?...You bet!...Is there a difference in terms of performance?...Yes,there is...Will you notice it much at first?
maybe and maybe not...the best advice I can give is that you should try some gear out before you buy anything...
Once you have had a chance to see a few things you will be in a much better position to ask the right questions (for you and your interests) and find the right gear for you.
The best scope is the one that you use...
Good Luck and enjoy the hobby!