A very decent result in Europe for Arsenal midweek which will raise their morale after some minging league form (4/5 league losses). Even without that I'd still fancy Arsenal to stop the rot against Watford, it just has to end sometime. As much as Wenger is looking like a manager overtaken by younger more progressive coaches, he hasn't forgotten how to play football, it would be no surprise to see his team pick up the W.
I like Watford's spirit, up to 9th after some earlier poor form, and the usual change of manager. Safe from relegation, nothing to lose against a home team that might get nervous if they can keep them at bay for the first 30 minutes.