Windows 7 Ultimate 64bit continually increases RAM usage?

Hello everyone, I was wondering if I could get some help.
I use Win7 Ultimate 64-bit, and it continually increases RAM usage. I don't my PC off very often due to me just being impatient and not wanting to wait for the reboot process, so I just leave it on. However, upon boot ram usage is at about 40% of 4GB. This is because I have a decent amount of things running in the background. After about a day and a half, RAM usage without anything but normal startup items running, increases to 70%. I have tried many things and even killing some processes still leaves the ram usage very high due to the blasted SVChost.exe process which I understand is necessary for the system to work, but angers me because it launches itself in many instances each of which uses obscene amounts of ram.

SPECS:
AMD Phenom II 1055t 3.38GHz x6
Corsair 2GB DDR2-800 RAM
ASUS M4A78 Plus Motherboard
Zotac Nvidia 9600GT Video Card
Windows 7 Ultimate 64-bit

Screenshots of running processes is attached. You will notice that sidebar.exe, Skype, Steam, and Firefox are all using obscene amounts of ram. When the programs are ran upon coldboot, they use much less ram, and their ram usage just increases continually throughout the time the pc is on. Same with SVChost.exe

TL;DR - How do I decrease ram usage so it doesn't continually increase upon the PC being on?

All help is greatly appreciated!

because it is very hard to do anything much less run games when your system is idling with no active apps and using 95% of 4GB of ram.

Any memory leak fixing utilities out there?

Britton30 said:

Also you should turn off Steam, Skype, and Gadgets until you NEED them. I use no gadgets myself, seems like "fluff",i.e uneeded stuff. Increase your Page file size or set it to System managed, it is slower than RAM but will lower its usage.
Don't be impatient and turn the machine off, say, when you go to bed.
Look at what starts on each rebot and disable those RAM hogs, they will start just fiine when you need one.

That is all true, but I use my gadgets quite frequently, to get Playstation Blog updates and see my network info. Also, I use steam and skype to communicate with friends, that is the reason I always keep em on.

EDIT: Thanks so much Mike for Memory Cleaner! That is EXACTLY what I wanted
Also thanks Britton for your advice :)

/solved.

Mike Connor said:

You are expecting too much of the machine. Running all that stuff continuously will only cause problems. There is no point in it either. Applications start quickly enough when needed, there is absolutely no advantage in having them running all the time.

Regards....Mike Connor

My point in running them all the time is the same as the reason you leave your telephone plugged in.

Thanks for the help and advice :)