Not all roundwound strings are created equal. If you hate that metallic sound, I would avoid Stainless Steel Strings. Nickel wound strings would be suited for you. I have had great experiences with D'addario XL's. After a while, they mellowed down to where there was no string noise. Also check out DR Sunbeams and DR Nickel Lo-Riders.
IMO, you should not get flatwounds unless you're going for a particular kind of tone. Don't get me wrong, flats are VERY versatile. But you won't have the kind of tonal versatility that rounds have.