Well, upgrading the platform would be more than $300, but the biggest thing I see is the monitor. That's pretty tiny by today's standards. I've seen 23.5 inch 1080p monitors running $160 and less, even with LED backlight. That would leave enough to get a 60 GB SSD, although I would personally get one of the Vertex II SSD's in the 100-120GB range. They are running about $2/GB which while its not ideal, its better and I think well worth it in terms of system responsiveness. I was a naysayer for a while..until I bought one and now I can't see going without one.
I've got a similar model acer and the blacks are pretty black at contrast ration of 80k:1. What do you use your pc for mainly? Like buzznut said, the leftover $$ can get you a decent 60gb ssd that'll increase speeds tremendously on your pc and be a nice upgrade.
2 ms is better than 5 ms but I'm not sure how big a difference it would make to the naked eye. My aver is 5 ms and I'm happy with it. Like any hardware purchase, do a little research on it. The contrast ratio diesnt appear to be that great to me, but I'm not a monitor expert. As I understand, the CR just shows how well black is displayed. But I've had my monitor for almost 2 yrs so contrast ratios might not matter as much with newer monitors...
It's gotten some pretty positive reviews on newegg, bug I couldn't find any reviews from cnet & the likes. At that price, & in your shoes, I'd order it if it were me. You could see if your local shops have this model & see it in person before you buy. As for the contrast ratio, I didn't see any complaints about it. I'm on my iPhone & at work so I can't do much research but I'm sure if you googles it you'd find more info.