Corsair is good, as is Mushkin and Kingston and others. Each company tho makes several flavours. They all have value brands right up to serious performance brands. I myself love OCZ(I use their EL Platinum http://www.newegg.com/Product/Product.asp?Item=N82E16820146890), it's one of the top brands and I've never had problems with them. With memory, you get what you pay for, so if you buy cheap you will get cheap. The Corsair you pointed out is their value brand.
Remember, if you are adding EXTRA memory to your pc, the memory will perform at the level of your poorest stick. So if you buy some hyper memory and stick it in with an older crap piece, they hyper memory will perform no better than the crap piece.
Ok thanks for the replies guys, greatly appreciated. Now before i go pulling my pc apart, is there any way i have find out the specs of the memory i have without opening up the case. As i understand it there are memory sticks with different pin numbers, and then there is sdram and ddram etc etc. Just want to make sure the RAM i get is the correct on for my mobo. If it's any help, the pc is a HP Pavilion (shudder) model 8860.
My "best memory" is back in the day when I was little, all excited with the anticipation of Santa. . . . wait, that's not what you meant.
I just happened to be on HP's website looking up some stuff for my HP printer when I read your thread. I popped in your computer info and got the info below. Your best bet though is to email customer support from the place you are buying from and specifying the computer you will be installing the memory into. That way, if it was the wrong memory, you will have proof that you bought what they told you was correct, so you can avoid the re-stocking fee/no return policy that a lot of places have on memory.
Some of the manufacturers have a "questionnaire" on their sites that help you identify exactly what type of memory is compatible with your computer. I know this works with Dell PCs so I would imagine HP would too.
In regard to types of memory, you do get what you pay for. Don't be scared away from "value brands" as long as they come from reputable companies (Corsair, Mushkin, Kingston, etc.). Unless you are really doing something on your computer that requires horsepower, you would probably never notice the difference between levels of memory coming from a single manufacturer. I have Kingston's "value brand" in a machine at home and have yet to encounter a program or game that gave it fits. But then I would not consider myself a "heavy" user either.