I've been going to festival all my life from Glastonbury and Carling Festivals to local Folk Festival and am now bringing my 4 year old son along the same path.
Bands that have really stood out at recent festivals and have made me go WOW are:
Ukulele Orchestra of Great BritainOne of my favourite entertaining bands of last year

Their cover of Nirvana on Ukulele's has to be seen
BreabachSaw these at Cambridge Folk Festival after I walked past the tent and they drew me in. Very talented and tipped for best scottish band of the year.
Dreadzone
Nice idea but saw them at Glastonbury and they said it was to be their last ever gig
Vin GarbuttHave to put this guy in cos he's my local legend. Very Funny guy and very entertaining.
PS Cambridge Folk festival didn't put him on and now theres spirited movements and websites springing up about it :O
WOT! NO VIN?You've been warned
Horace XPsycodelic rapping folk band, is maybe the best way to discribe these guys. Very high octane and definatley get a crowd going. Consists of half of the university of cambridges music department i think.
Now depending on if these _link_s work properly and my browser doesn't pack in for a laugh then you should have a few good bands and singers I saw over the last few years. Enjoy.