Damn, I must have just missed that! What a deal! I got my FX5 used for a steal, but a brand new FX6 for $170 is the kind of thing you buy even if you don't need it right now.
As for the original question - I second the FX6 (or FX5, they''re basically identical, and you can find a FX5 used for a good deal sometimes). It's so easy to use, easy to clean, very powerful, and has a ton of space for media. Water changes are a breeze - I just attach a water hose to the purge valve, run it out the back door, open the valve and let gravity do the work.
My only complaints are:
1. plastic parts - The purge valve and the screws that tighten the cap have both broken on mine, and replacement parts are Fluval brand only and WAAAY overpriced.
2. hose diameter - you
can fit standard plumbing fittings to the hoses, but it's not a great fit, so if you're trying to plumb the filter into a more elaborate or DIY configuration, it's kind of a pain. Again, this is obviously so they can sell you their overpriced parts.