If I make a keyword as my domain name, will I be the first in search results for that keyword? Sounds a bit crazy
That is again a misconception - Yes there is some value added in forms of google giving you a 0.1% edge over competition because your keywords are in your domain name - Heck! Its the same with permalinks. Then again, having a domain name with your primary keyword is great for brandability and for type-in traffic and retentivity in some niches.
I'm going to stick my head out here and say that keywords in your domain name are almost as important as the anchor text of the backlinks you build. They will certainly help you reach number one spot that bit quicker and with less work.