Gaming Desktop

Hello summoner!

I am looking to upgrade from my cruddy laptop into a gaming desktop and was just curious about any good decently priced desktops out there (600-800 maybe?) but that number is not set in stone and I appreciate any info and recommendations. Also, would it matter if I didn't have a high quality monitor with it? Ie) I know the graphics wouldn't be as nice than with a gaming monitor also but right now I'm just worried about lag and smooth play. Thank you for any help!