If you're looking to store a lot of files, I would suggest an industrial looking metal one. Filing cabinets have ratings based on how much they store/get opened and closed, and the commercial grade ones are all metal for a reason - they withstand the beating. Something like this I guess.

David Allen's recommendation on filing cabinets, if I recall correctly, is that they should have drawers with bottoms (not just sides for haning files) so that you can use manila folders, not hanging folders. He also recommends cabinets with mechanisms to push folders forward inside the drawers, so that the manila folders in the back don't open and spill out. Here's a link to one for HON cabinets.

Unless you're only keeping something like a year's worth of bills and statements in the drawers, I would recommend against Ikea filing cabinets. A lot of Ikea drawers have sides only, and or have flimsy cardboard drawer bottoms that won't hold up against the weight of all the papers at full capacity. For example, Gallant filing cabinets have no bottoms, which means hanging files only.

If you're still thinking Ikea (because they do look pretty good IMO and prices are very reasonable), I've seen doctors' offices use Kallax bookcases to store a lot of charts (which are essentially folders), and they seem to hold up to the capacity and frequent use.

The folders would go in vertically and sideways in this set up (like how you would store books and LPs in them). Folders for patient charts have tabs on the bottom with label stickers, so they just put them in the cubes directly, but you can buy additional accessories to add drawers/make hanging folders work - here's a set up. Kallax/Expedit is the only thing from Ikea that seems sturdy enough to hold the weight of all the papers (if there are a lot), and it comes in many different sizes.

Lastly, this might have already been mentioned, but a good duplex document scanner like this one costs about the same as two good filing cabinets, and would save a ton of space.

Good luck!