.coms are more valuable than .nets as .com is what people associate to be the end of a website address and so will remember it easier.
generally choose a .com over a .net - sometimes a good idea to buy both if available (like madmax said).
Again if you have really big plans for a site then .com is probably better. But it is not the most important thing when making a site. If you design your site well and run it well then that will be what makes it a success. But a .com catchy domain name is always a good bonus |cool|
Just my 2 cents
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