If your Toshy laptop at work seems like a POS, then I am guessing it is just old & slow.
All the more modern Toshibas I have worked with or on have been a pleasure...and they are usually very durable, as well. Toshiba laptops have rightfully earned their accolades as one of the very best line of machines out there.
As for the Dell; there have been some problems with power supplies shorting out and burning houses down; I understand there is a recall underway...read about that here.
I have seen lots of issues with Dell LT's, although the hardware seems to be slightly better than that in the HP and Gateway laptops; FAR better than the Sony or EMachines and about even with the IBM.
All laptops are similar in some ways; all builders sell models that have longer battery life (replacement batteries are pricier), or bigger displays (VERY pricey to fix a large LCD), and all OEM's sell Bargain Laptops. You'll be sorry if you go for one those models, trust me.
Buy for the future when shopping for a laptop; get a larger hard drive than you think you'll need; remember that RAM = speed, and that a Pentium 'M' CPU is cooler and faster than a Pentium 4...read some reviews for each model that you think will work for you.
In all honesty, the problems usually come from all the mouldering refuse they bundle as 'value-added software'. It is meant to look like you are getting more for your money, but it is all just junk they crap the OS up with to stuff the OS up proper, in order to afflict you with their Support Lines.
Half of the time, either the antivirus doesn't work porperly or something in AOL's Trial Offer, or the Dell-branded HelpCenter, and just tries its best to fudge the machine to the point where the owner calls Tech Support in Abu Dhabi or somewhere...and then gets an invitation, in broken English, to provide a valid Credit Card number in order to cough up money for said support...just to fix a problem that Dell intentionally built into their product!!
I hate OEM's. Get a local shop to support your laptop, no matter what; the frustration saved is worth the expense. All the OEM PC's software ills can be cured by a heaping helping of fdisk with a side of XP Professional (and a Debian dual-boot...but that is a different article).
As I said, call around to the local shops that support laptops and let them know what you are interested in doing with it. DO NOT tell them that you will be bringing it to them for service (you'll probably get a cheaper model this way; most likely a model that they get in for repairs A LOT...hence they might be good at fixing it, but the total cost of ownership to you will be higher).
BTW, it stands to reason that you can safely weed out the shops that advise you to get a cheap, breakage-prone machine, or places that advise you to buy a basic laptop now and then upgrade later, from the list of people you want to do business with.
Then Google their suggestions, with an emphasis on Gripes.
And when you thinkm you have gotten it nailed down to the One Perfect Laptop, go to a retail store and type something on it...no, I am not kidding. Most gripes about a laptop come from people being unhappy with the touchpad, the key size or layout, or the action of the keys themselves. For an investment as large as this, you WANT to make sure it fits you BEFORE you drop a couple thousand on it.