#1
A tuner (planet waves chromatic pedal tuner (the £40 one)) or a noise gate (Boss NS-2, more expensive at about £60).
I have a bit of noise inbetween playing, but i also don't have a means of tuning apart from using the computer.

Thanks all.
Gear:
Epiphone SG-400 (w/Hot Slags)/Chapman Guitars ML1 > Digitech Bad Monkey > Blackstar HT-5 > Danelectro Fish and Chips EQ > ETI Chorus Flanger
Snark Headstock tuner!
#2
If you're getting an excessive amount of noise and its getting on your nerves, i would get the Noise Gate as long as its a QUALITY one.
#6
Go used and get both.
Spin 'round carousel when your horse isn't screwed in.

My band:
Fractured Instinct
(For fans of Death/Groove/Prog Metal)

Ibanez RGA42E
Ibanez S420
LTD H-301
Ibanez RG520
Peavey Predator USA
Douglas Grendel 725
Line 6 Pod HD500X
#7
A tuner is definatly more required most of the time.

I've never felt the need to own a noise gate.
"In modern music, a lot of people are really stuck on the example, asif it were the idea. It takes millions of examples to articulate an idea, so don't get stuck on the f*cking example." - Joshua Homme, 2008.