I use them, but I see the phrase without commas more and more frequently, especially in newspapers, which was why I asked. It's an opinion and not a part of the main sentence, so it should be comma-ed off, IMO. ;-)
I totally agree with you guys that the commas are necessary. Would they also be necessary with "in fact"? I ask because every time I put "in fact" between commas, Word says that it should have a semi-colon at the end.