@Ertain Yes, Dell is high ranked on my list: my 10 years old computer was bought on Dell Pro website (a Dell Vostro 430 with a i7-870 ). I'm still using it and 10 years old with all daily work is exceptional. But it starts to get electric bugs and tired motherboard/power block. Unfortunately! Still, if they still have good reputation that's probably worth studying them again, even going 1,5K budget...Thanks for the idea.
@davidrevoy @Ertain Lenovo also just recently launched a big linux initiative that includes some workstations, may be worth a look depending on your opinion of them.