Basically, this is to see how much internet I've burnt on GoG downloads and once I start doing MP and MMO stuff, to make sure I'm not taking too much more than my fair share, so does anyone have one of these that they've used for a while without problems, from a safe download site?
Win7, 64bit, decent computer so *some* processor power shouldn't be a massive issue.

Try NetLimiter.
I haven't used it in ages but it may be exactly what you're looking for.

I personally use the Firefox add-on Net Usage

You just choose your ISP and enter your information and it shows uploads, downloads, and what's left, depending on how you want it shown

Ok, I use several browsers plus other things, and its a shared ISP, so I'm looking for something that specifically monitors network flow in and out of my specific computer, as well as being able to turn it off when I'm on a different network that I don't care about using data on, do either of the above still work given this? :)

NetLimiter should work (Monitor is the free edition and does just that, monitors traffic, the paid editions allow you to limit bandwidth usage of applications as well).

Tried Net Limiter, is creating some problems with occasional lag moments, won't uninstall, can't find it on Processes to shut down so I can delete it, and doesn't have (or at least, not easily visible) what I most wanted which is a "total data usage" stat. Thanks, but it seems its gone downhill since you used it.

I've been using a program called NetWorx for the past 8 months and I've been pretty happy with it. It seems to have a fair amount of options, although it won't limit your bandwidth.
I haven't run into any problems (lag or otherwise) since installing it.
You can get it here: http://www.softperfect.com/products/networx/

I should add I'm looking for free programs too >.>
So does yours fit the free as well as total data usage options Gref?

Thanks heaps to everyone who's replied so far btw :)

Yup, it's completely free. 8)

Thanks, looks like its what I was looking for. Should have made this a question to give you the forum kudos for it :P

No worries. Glad it helped.