IMHO, go with Standard. The Line 6 version will tie you to your Line 6 device (or any Line 6 device for that matter - GuitarPort, TonePort). Standard lets you use your Line 6 devices and any others.
It's true that you can use any asio device with Standard, but if the PODXTL is the only one your gonna use then you could just stick with the Line6 edition. With the money saved you could buy a few drummers. I very rarely use anything but Line6 even though I have the Standard version. Maybe because the Line6 models are that good I dont feel the need to buy anything else.
BUT..........with the Line 6 version ......you won't be able to use Giutar Rig 2 /Amplitube 2....ETc....ETC
Standard is the way to go my man.............
I too pretty much stick to Gearbox / Line 6 products but have the flexibilty to use the above when needed plus loads of others........like VST FX and such.