Welcome to IIS, silwat!
The 10mm and 25mm EP's will get you by for a while, but you'll probably want to fill some gaps with a reasonable quality 2x barlow, and a 15mm. You can get the barlow and 15mm plossl for a good price from Bintel, MyAstroShop, etc.
Don't forget a star chart and red light torch!
The 8" dob is a great scope to start with.. you don't
have to modify it until you get familiar with its uses and limitations.. but to get you started, have a wander around the
Articles and see what others have done to their dobs and you can get some ideas.
Don't forget, keep asking questions!