Another piece that works really well for cutting straight lines is a reciprocating tool, like the Fein Multi-master and it's clones. The circular blades cut through drywall like it's butter and it makes dust, but less than a Dremel. It doesn't have a dust collector attachment, though. The blades will become dull, but it will guide itself to a degree. I bought one from Harbor Freight and it has paid for itself many times. The blades are a lot less expensive than the ones from Fein, too.