Rather than suggest any particular machine I will list my favorite features on my best machine(Babylock-10 yrs old):
thread cutter -saves thread and most of the time no trimming of ends
ability for automatic lifting of the presser foot when stopping(needle is set down, foot raises - perfect for pivoting);
feet that press on and off(unlike some machines that require a screwdriver to change feet)
I find it's the little things that save you time and effort that are appreciated the most.