Hi Ruben,
What kind of recording will you be doing?
If you're doing recording that requires acoustic sound from guitar/piano/etc or vocals, you will need mic(s).
You can either choose USB or normal XLR connected mics. (i'm using a usb condenser mic myself which does not require an audio interface.) XLR connection mics require an audio interface.
* You may need to do sound treatment or proofing for your room. That one i'm still researching
I'm looking at some foams or sort.
If you're doing MIDI also, you may wish to purchase a midi controller. (i'm using a korg61p, cheap cheap, and good enough for home production).
If you're doing several instruments at one time, you may need a mixer, especially if the no. of instruments are more than what the audio interface can handle. (i'm not using one. I do multi-tracks, but doing layering, be it midi or audio, one at a time.)
Misc items: Mic stands, pop filter, cables (1/4inch), keyboard stand, etc.
HOWEVER, you must specify what kind of recording you wish to do before one can actually assist you in building your home studio.
All the best