I had the filter dilemma before Christmas, my aquarium is 60x45x45cm, so around 120 litres. I wanted to avoid adding a powerhead for aesthetic reasons and I wanted the heater outside the tank and had seen some horror stories about the Hydors, so I went with the Eheim Pro3e 600T. Admittedly I am having to buy a second house to fit the filter in as its actually the size of a small car, but its rated for 1850lph, so even with a drop in flow for an inline CO2 atomiser, I am hoping to get good flow when I get it all set up. It's an expensive filter though, around £500, so its half of your budget...