Hang on everybody - are you all saying your legs aren't tired during the day? Mine feel tired pretty much all the time when I'm not running, which I take to be a sign that I'm training well! I don't run upstairs much any more because unless I'm warmed up it would be too uncomfortable. You lot are probably so used to the feeling that you don't notice it any more - so keenrunner, you might just be feeling the perfectly normal effects of working out hard and effectively.
Otherwise I'd definitely recommend getting into sports drinks, as they really make a difference - my favourites at the moment are Lucozade Sport (not the Orange flavour which is a bit yucky), Gatorade (tangerine flavour, yummy) and Isostar (orange flavour). And if you really feel in need of more recovery after a hard work-out, I'd suggest something like High5 Protein Recovery drink (my favourite is chocolate milkshake flavour), which not only replaces glycogen but protein as well, helping those sore muscles to rebuild much quicker. (Protein recovery bars are good too.) There's plenty of stuff out there to choose from, it's a question of finding what you like drinking/eating. Sometimes, ordinary food isn't quite enough. s.