I use a stainless steel kitchen strainer. Once I cool the wort, I rest the strainer on top of the bucket and just pour the kettle into the bucket through the stainer. This has the added advantage of aerating the wort. Of course you need a big strainer, or someone to hold it for you. I use my 5 year old daughter for that. She's also useful at bottling time.
Sometimes it will get full of sediment before all the wort is in the bucket. In that case, I just keep pouring and don't worry about what gets in the fermentor. You can always top off to the 5.25 gal point to make up for some of the trub loss.