The price per gigabyte is not low enough. Also I wouldn't want to upgrade anything else before replacing the built-in keyboard (some keys don't work). I am fine with the speed of a hard disk drive. SSDs are too expensive and I don't need one. RAM is more useful.
This is the last time I am going to explain. SSDs are out of the question so DON'T MENTION ANYTHING ABOUT THEM! 19/20th of the replies are useless "get an ssd" posts. -_- it really pisses me off.
You need to drop the attitude.
People are trying to be helpful. How about you gave that explanation FIRST instead of treating people on here like crap. Their advice would've been different.
Now we understand, you want storage, are not worried about speed, just price. Fine. In that case read below.
Blow out the dust from your mac with compressed air. 99.99% of "hard drive noise" queries turn out to be fan noise. You're describing a whooshing sound, that's air moving. The most likely thing that is going to move air is a fan.
This could be down to the hard drive as faster drives run hotter, hence will activate the fans more quickly than a slower drive. You could replace the 7200 rpm drive with a 5400 rpm drive of similar capacity. This will obviously be slower, but may well be significantly quieter.
Some computers temperature sensors very near, or even attached to the hard drive. They can easily be damaged. They will default to full fan speed if that is the case
My other thought is vibration.
Do you have any dents in the bottom case? MacBook Pros are made of aluminium, and so dent easily. A spinning hard drive will obviously vibrate. If for some reason that vibration is transmitted to the casing, it will amplify that vibration, which you will hear. There are two ways around this, straighten or replace the dented casing, or use thin and small (and I emphasise small) strips of self adhesive rubber to the hard drive at the point that it is touching the casing. This will cushion the drive from the casing, and by only using it where there is some direct contact with the casing you are not affecting cooling. DO NOT cover the vent on the drive under any circumstances. If you do, the drive will be toast very quickly.
One last thought to do with fans.
You have some malfunctioning keys... Why? Did you have a liquid spill on your computer? If so, then that may be causing the fans to work overtime. To fix it is a logic board repair or replacement. At that point, depending on the age of your computer, I'd be looking to replace the machine.