Ouch. Misinformation abounds here.
Let me clear some things up.
Sony & Toshiba can't honor their warranty claims. I've dealt with both first hand both professionally and personally. Never, ever, ever again. I recommend, HIGHLY, that you do the same.
There's no such thing as "too powerful for college" - really, what's the idea behind this? If the price of the system fits the budget, why is buying more power than you need a bad thing? It just means that in 2 years or so when the system has "aged" you won't need to pull the upgrade trigger very soon. You should ALWAYS buy as much processor power, RAM, disk space and video capability as you can afford.
I also disagree with the whole "buy a desktop when you finish" - Laptops are infinitely more useful today than they were 5 years ago. Even 2 years ago. Performance deltas, especially with Intel i3 and i5 based laptops are much closer to desktop performance than most people give them credit for. I use a Core 2 Duo in my laptop, and coupled with an SSD for the boot drive, it is indistinguishable between my performance desktop PC in most tasks (as seen in my siggy below)
That being said, a laptop with a price point of $600 is going to be plenty for most people unless you want to use it for gaming, then spend the extra money and get a REAL video card like a Radeon or GeForce. Do not, and I repeat this with blood on my fangs, DO NOT BUY INTO INTEL'S CRAPPY "GRAPHICS". You WILL be disappointed down the line. I have first hand experience here too. I wish Intel's graphics ambitions would die like Osama Bin Laden. Same style too. Meh.
Going to Best Buy to try one out is a good idea, just don't let them talk you into a sale. You can do much better online, and even when you call a vendor. Just mentioning that you're a student will often incur heavy discounts. My Dell XPS M1530 was normally $2200 brand new (because of what I loaded it with) but I got it for $1400 just because I gave them my school's name and my school code. (info varies, definitely check with your school before you're ready to buy, just in case they also have discounts available)
Lenovo is a decent brand - I trust the systems now more than I did the IBM counterparts. Lenovo fortunately knows more about laptops than IBM ever did. We use them at work, and they're pretty decent. Just be sure, as I said, to avoid like the plague, ANY and ALL Intel graphics solutions (Intel Graphics "Accelerators" are NOT accelerators.
I'm still hazy on HP, they've had some Quality Control issues in the past few years, but I haven't heard anything overly negative about them in the past 6 months.