I generally recommend .com. You can still get a pretty decent domain name if you try a bunch of options and put some thought into it. (It has to be 5 letters or above; I recently confirmed that every 4 letter or fewer domain name is taken.)

.com has legitimacy, it's not going to have hiccups (some country code domain names are pretty iffy, like .io had issues a while back), and contracts with ICANN ensure it's not going to extort a huge price out of you.