the rosewill may be abetter price, but mushkin is a good brand, and it is known throughout the tech world. so isn't corsair, kingston, OCZ. mushkin is the cheapest of the bunch I believe. they are all good brands that users here will reccomend. I can't say anything against rosewill though, since I never had any.
but the 3200 is better because in the future you will be able to use it.
right now, the pc2700 is not using you fsb to its full potential. the celeron has a 400mhz fsb ( i am pretty sure it does) so with pc3200 memory you will use the fsb to its potential, and if you upgrade, you will have some memory to use that is pretty good.