1. Is a DELL better than a Toshiba?
This is the Ford or Chevy question. If only the answer was possible. I'd get back to what it costs, what it is and what your needs and goals are. BOTH makes have good machines and terrible software support.
2 Is a 1.6 GHz i7 equal to a 2.8 GHz Core 2 Duo [or a 1.6GHz is a 1.6GHz, is a 1.6 GHz; whether or not it is an i7]
No. Get to reviews and see the benchmarks. And NO! You can't use one benchmark. A high games frame per second does not mean it will win at some video editing task.
3. Currently deal with a lot of graphics, Oracle stuff,
All this does is dismiss any value machine. That is, 1GB RAM, single core. It does not dismiss the Intel 4500MHD or such solutions.
4. GIS applications at work [Geographic Information Systems, maps and tracking]; I am just trying to replace my home laptop [don't laugh!] a 2002 model DELL Inspiron windowsXP with 500MB RAM.
Initial budget was $500, but browsing now on the DELL site it seems I may have to spend $1.8K-2.1K.
[Costs $500 extra because I am including a Blue-ray burner and going from a 4GB DDR3 RAM to a 6GB]
I too was waiting for the Windows 7 roll out and was eyeing i7 machines but didn't find one I would pull the trigger on. I ended up with the hp dv6-1361sb. It's fast but as suspected is not silent and is not for those that demand cold surfaces on the laptop. I have only one quibble that is something I'm adjusting to and that's the keyboard. My bet is the keyboard could be something I have to learn with any new machine. But say with some, the home and end keys vanished which for me is not acceptable.
-> I'd look at simpler Core 2 Duo 2.0GHz machines with the usual 4GB RAM, Windows 7 64 bit and the Intel 4500MHD or better solutions.
Bob