has anyone got i any good map ideas i could try to model.
and what does everyone like for the tagset

yeah, from halo 3

It's not always about what they like, because it depends on what the map ends up like. For example, if you start to model a snowy map with underground tunnels, you may want to choose a halo 3 tagset because of all the close range/melee weapons you have. Or if your map end up new mombasa-styles, you could choose a fitting halo 2 or odst tagset. What people want doesn't always make good maps-- there are a few reach maps out nowadays, but the bsp models are not so good, or the weapons were thrown into an already existing bsp.
Er... I suggest you model... an island? Haven't seen an island in a while. For lulz make it snowy. There aren't a lot of snowy island bsps... high tide is the only one i can think of?

Thanks great idea i love island maps and i don't think i have ever seen snowy ones

I like the cortana map idea.

How about, a Halo 3 themed Cartographer map? The halo 3 cartographer bit, I mean. Its a pretty good design, red base could be on the Cartographer building, blue on the entrance to the entire area.

Of coruse edited a bit to support multiplayer.