wow okay you picked to amazing guitarists there with some what similar styles. both created amazing riffs just look at smoke on the water - blackmore and whole lotta love - page both hugely well known riffs.
in the way that there styles differ:
Jimmy Page was more influenced by folk than blackmore if you look at some of zeppelins stuff such as going to california very folky an he was also very blues based in his approach. i dont think there is a particular song that covers jimmy as his styles vary so much, also not only was he a great guitarist but he was also amazing at arrangement. songs to look at for his diferent styles are
1. Stairway to Heaven (obviously, shows his folk roots with an amazing arrangement, the best solo ever written(no arguments!) an a kick ass riff!)
2. The Rain Song - most beautiful thing to have come out of a guitar! arranged by page its damn damn good!
3.Since I've Been Lovin You. - My favorite ever blues track again amazing solos!
right okay cant be bothered going on any more so there are just three.
Ritchie Blackmores style was similar but id say leaned further to the classical side of things. (as far as i can remeber not quite as big fan of deep purple) songs often used more organ, at first found it off puttin but soon got used to it. to some up his style hmmm kind of difficult in one song again my favorite album of theres was deep purple in rock.
Overall i'd say zeppelin had a more eclectic style (encompassed and played more styles) than Purple judging from what i have heard. if your gonna buy a zeppelin album i suggest remasters (its a best of really, got a hell of alot of stuff on but expensive cos its double cd) or any of there older albums avoid coda and in through the out door