I Highly recommend building it in peaceful, pvp can be risky sometimes, especially for new players who think its ok to warp to pvp
Probably a grassland. It would fit the sky scraper theme and how it dominates the surrounding area. Or you could put it somewhere like a forest biome. So that if you were looking for it it'd be rather hard to find.
All finished just need to stock some items ;D http://imgur.com/206hQ,6MIE8,7GyLX,Jfxnt,b2mqj,mvIWu,TawiL Oh and its at my /home until I get enough for a warp