non of the above.
either something small (say a wash cloth) that you can FINISH and have a sense of accomplishment!--
or something you have fallen in love with.
Scarves are easy, but endless.. (i knit fast and they still are so long to me, i complain!)
hats require shaping/seaming.. (not too hard... but they hang around your face!)
wash cloths (OK the first few can be dishcloths) but they are small, they offer the opportunity to learn stitches and techniques,
they are many EASY patterns.. but they can be building blocks to advanced skill --(like knitting in the round, or cabling, or color work)
the get used and washed frequently --and you learn, that washing and lying flat (ie blocking) does wonders to make a wonky knit stitch into a perfect one!
Conversely, some knitters have knit HUGE MULTICOLOR projects as a if not first, 2nd or 3rd project.
YES, it was overwhelming.. but they LOVED the project and plowed ahead.
What the best project for you? only you can decide!