G502 for the mouse.

The Beyerdynamic DT990 is where is is at, most go for the closed DT880 because it is cheaper and I have listened to them and was so happy I spent the extra money for the semi open 990s. Everyone that owned 880s who then listened to my 990s said they would be saving up and trading in for the 990s.

These are the best you are going to be able to get without spending an insane amount of money. I used them for a few years with a simple little dot mk1 amp and just used a soundblaster card as the dac until I saved up and got a DAC amp from Audio-gd.

You could likely find some cheep stuff from Schiit as far as dac/amp goes I hear the Schiit stack is supposed to be good but I have never heard it personally.