It really depends on what the machine's purpose is, and your expertise with using the operating systems.
Personally, I use Linux on any computer that I have a say-so in what is installed. But, for the average user, Windows may make more sense to use.
First thing you should make sure of is that the hardware in the laptop is compatible with Linux. Nowadays the hardware support for Linux is superb, and most likely there is a driver or workaround for all of your hardware. My last install of Ubuntu 10.04 LTS found every driver on the first try!
If you're going to use the laptop for games, web browsing, and general computer usage, you may be better off with Windows. I haven't been a fan of MS since XP, but Windows 7 is actually pretty nice.
All-in-all its more of a question of what are you going to need the laptop to do, and which OS can do it better.
Or, if you've got the hardware and HDD space, set up a dual boot! I recommend installing Windows first, and then Ubuntu, if you plan on a dual-boot situation. Doing it the other way has caused me too many headaches in the past, although it has been since XP/Ubuntu 6.04 since I've set up a dual-boot.
(Side note: I am software developer mainly using Java and Android, so if you say Linux, which distro would be work well with those needs) – Adam – 2010-07-08T13:54:00.757
3It's impossible to objectively answer this question; questions of this type are too open ended and usually lead to confrontation and argument. Voting to close. Try and answer other people's questions first... Just see what kind of questions are asked here and gradually become aware on how this site works. – BloodPhilia – 2010-07-08T13:54:08.087
2FWIW, the non-subjective portion of your question confused me. You say you are are buying a "new laptop". Perhaps you can get a laptop with Linux pre-installed, but it's generally not worth it. Windows 7 is cheapest when included with a new machine. I would recommend getting a Win 7 laptop and then dual boot a Linux distro as Mistiry suggested (below). Possibly do extra research to determine which laptop best supports your preferred Linux distro, though I'm not sure where you'd go for good info about that. Linux discussion groups maybe? – irrational John – 2010-07-08T14:19:30.293