New Laptop for Software Development

Hello,

Looking for a laptops - here's the requirements (as requested on the forum sticky). Any help appreciated.

Thanks,

Tom

1. What is your budget?
UK£1000 but if I can spend a lot less then great.

2. What is the size of the notebook that you are considering?
~15" screen

3. What screen resolution do you want?
>= 1280*800

4. Do you need a portable or desktop replacement laptop?
Bit of both - don't want it to be really heavy or eat power but needs to be quite powerful

5. How much battery life do you need?
>=3 hours

6. Do you want to play games with your laptop?
No

7. What other tasks do you want to do with your laptop?
Business software development - Visual Studio, local SQL Server database, MS Office (potentially all at same time)

8. How much storage (Hard Drive capacity) do you need?
>=100GB

9. If you are considering specific sites to buy from, please post their links.
No

10. How long do you want to keep your laptop?
>=3 years

11. What kind of Optical drive do you need?
Don't care - DVD RW would be handy

12. Please tell us about the brands that you prefer to buy from them and the brands that you don't like and explain the reasons.
Decent brands without paying through the nose.
Needs to be reliable.

13. What country do you live in?
UK

14. Please tell us any additional information if needed.
Looking to buy 6 so need to be confident I won't get complaints from everyone.
Previously bought lots of laptops and found the noise and heat from dekstop replacements causes a lot of complaints.
If someone can explain which CPU I should go for then that'd be great - completely confused as to the meaning of Intel i3, i5 and i7 as they seem to have different specs even within each category.
Be nice if a similar model were still available in a year so I don't have to search again.
Needs 4GB memory.
Don't need an OS (look at the MS ActionPack if you're in the same boat as me.)