Depends what it would be used for. Windows 7/64 bit on a 2GB machine seems a bit, how should I say, cramped. But again, it depends what you are using it for. If you can double the memory on the cheap then it's a sweet buy. " If "
Memory pricing is really decent right now because PC sales are way down. The key thing here is how the computer is populated with that discounted configuration.
Matched pairs of notebook dimms are crucial (no pun intended). If you can match the one in there (speed and timing) then you're golden - however, if it's a knucklehead 2GB with two 1GB dimms taking up two slots then you would need to need to consider how to proceed. Personally I don't mix & match memory vendors - it can be problematic. Even so, an 8GB kit from Crucial is still very inexpensive and 8GB in that machine would kick the performance WAY UP, both in terms of Windows performance and graphics performance.
That 15.6 inch screen is really nice for that price too + the "plenty big enough" hard drive. HP/Compaq rigs are durable.
I use a USB keyboard. Some chain a USB mouse allowing you to use both on one port.
Those pads are crap. I'd recommend bypassing it and also using the external video if you are going to use it as a home computer. three USB ports should cover external drives as well.