suggy
all trades in fx are pair trades really. ie you are selling one currency and buying the other at the same time.
However, the "majors" are all measured against the USD, ie eur/usd, gbp/usd, usd/chf and usd/jpy. (USD/jpy is not really considered tradeable at the moment due to BOJ intervention producing some huge price spikes, however a year or so ago, this was one of the smoothest trending fx markets)
Tha main pairs that people seem to use for daytrading are eur/usd and gbp/usd as they move well on the shorter timescales.
I personally trade slightly longer term, few days to a week or so generally and I track the majors and a number of crosses (crosses could be deemed as "pair of pair" trades as they combine say eur/usd and gbp/usd to give the eur/gbp cross. I trade each one if they give me a good signal. What tends to happen is if the majors are not tremding very well, the crosses like eur/gbp, eur/chf eur/yen etc can get some good moves.
In short, if you are looking to daytrade, I would say stick to eur/usd and gbp/usd at the moment.
If you want to position trade, try tracking the majors and a number of crosses you like the look of. You'll have more time to track a number of pairs than if daytrading.
I would suggest just having a look at different pairs charts over different timescales. You will soon see which move best short term and long term.
Best of luck
Darren