SS:
Ron: Nothing
Hermione: Chocolate frogs
Though the gift is generic it shows Hermione to be more Harry-thoughtful than ron. Foreshadowing anyone? But remember Harry hasn't yet learned to appreciate Hermione as he should.
Cos:
Ron: Flying with the Cannons
Hermione: quill
Hermione's relationship improves and she moves from generic to useful (a step for her I imagine) whereas Ron gets him a present a little closer to his heart and still gets best friend position.
Poa:
Ron: Not specified
Hermione: Not specified
(Ignore this year.) This year the relationships (even stupidly-loyal Harry/Ron's is ridiculously skewed to hell). At the end though Harry at last recognizes Hermione as Ron's equal and thus:
GoF:
Ron: dungbombs
Hermione: Quidditch Teams of Britain and Ireland
Ron moves to dungbombs which I suppose are a mixture of generic/useful, but Hermione (the only one to believe his not entering himself into the triwizard tournament) gets him the gift closest to his heart now. See the switch?
OoTP:
Ron: bertie botts
Hermione: planner
Ron moves to a gift completly generic, (he's equal now with Hermione in SS) which makes sense to us given the fight with Harry in the previous year and how little in the book he is in year 5, but Hermione who is at her pinnacle of importance, and without doubt Harry's closest friend (closer than Sirius even) and who obviously feels more for Harry than Ron at this point (romantically or otherwise) gets them both the same gift? reverts back to the useful gift year of year 2? The only reason I can get from this is her starting to realize how important a certain someone (I suppose the R/Hr could argue she realizes her feelings for Ron) but whoever she's feeling anything for (I don't need to explain our copious HHr thoeires to any of you do I?

) she trying to distance herself. (And for all the R/HR shippers--did any of you see Hermione's reaction to HARRY's christmas present--that lovely book? that should help clarify a few things...)
HBP:
Not specified for either. This is equally telling--and shows how OOC the characters are, by the way: I got this off wikipedia and not my own biased sources:
"The sixth book[HP6] marks a notable change in Hermione's character. "
......wait......