I got an Ideapad y580 a couple years ago, which appears to pretty much be a couple years older version of the y510p you're looking at. It has 4 USB ports, HDMI, and is capable of running at full heat for a very long time (EG all bloody day). The screen is only 1366x768, but the card can handle a lot of games on 1080p (I use it with another monitor on HDMI a lot). The case is really solid, the battery life is OK, and I had one hard drive failure but no problems besides.
So, I think I can recommend the ideapad, Lenovo seems to build their stuff well. Also, it will handle any game you want it to run with freaking two 755m's. The RAM and CPU will also carry your video editing. That does seem like a lot of power, so you should check reviews to see if it overheats or anything, but if it's like my older model it will have a monster heat sink on it (oh yeah, if I have one complaint, it's a little heavy but this is what we call a "Desktop replacement"). Sucks that you bought a Dell laptop before, those things are awful. A friend of mine got one of those, after a couple years of use (and yes, cleaning the fans) it overheats too much to run basically anything.
If you do get the ideapad, one caveat, it has both integrated and Nvidia graphics to save power some of the time. HOWEVER, it will often use the integrated graphics when running a game Nvidia has never heard of before, which is relatively often for me. You can just right click the program and choose "run with... Nvidia HD Graphics", as well as set that to be the default for that program. Another caveat is that I've heard SLI rigs can have occasional weird problems in general, and require a little more user input to run well. I haven't personally used one before.