do it man, alot of people are biased against that stuff but you have to do things for yourself sometimes.. theres alot of interesting fish you could techinically do in a 3 gal.. i wouldnt say a clown per say (they do grow man )
It would depend on your light, easiest and most colorful for beginners are nice zoas... if you like those corals then go that route could have yourself one neat little zoanthid garden!
theres plenty of other LPS id suggest once you tell me the lighting
Well I'm running the stock light which is a 50/50 power compact coralife 9W, but that is always upgradable. I was looking into Green Star Polyps which I really liked, but i love Zoas too.