Not sure what you're using your puters for, but $1100 is an awful lot. I built mine over 5 years ago, Asus mobo, AMD Callisto dual core processor overclocked to 3.4 GHz, 8 Gb RAM, 1 WD 500 Gb hd, with case, dvd burner and power supply I was out $545. It still works like a brand new one right now. More money doesn't necessarily mean a better product.As far as my old computer goes:
5 years ago you bought an AMD Callisto overclocked to 3.4 gHz. That is a dual core processor. I bought my system in 2012 with a Core i7 Quad core processor that ran at 3.4 gHz. That is comparing a coupe to a sports car. I bought 16 gb of RAM. In this case, more money does equal a better product.
With this new system, I am looking for a 17 inch laptop. I challenge you to find a decent one for less than $1K. I've been looking.
As far as Ubuntu, I have an 8 year old laptop that I am experimenting with.