It's the 'Bike to Work Scheme' you mean here I presume. The €1000 limit will also cover safety equipment, so make sure you get yourself good lights, lock, helmet, mud guards, pump, puncture repair kit, etc. This is a once in 5 years deal, you can save up to 51% on your total spend. If you can afford to, maximise the benefit and spend the full €1000.
Find out if your company has partnered with a 3rd party to administer the scheme, this will limit where you can purchase the bike. There are a few companies offering this service including biketowork.ie, bikescheme.ie, bikes4work.ie
Good brands include Trek, Giant, Lapierre, Specialized, Cube.
Leo