Many people's watch journey began with a TAG. Mine certainly did - I had had Casios and various fashion watches in the past, but wasn't an enthusiast by any means. Then in 2011 whilst walking though the shopping centre this caught my eye in the window, and I had to have it.
This is the Carrera Chronograph CV2010. It is powered by the Calibre 16 (also known as the ETA 7750 - the ubiquitous Swiss automatic chronograph movement found in many models). This model is 100m water resistant (there is a previous 50m model). I love this watch - it's very versatile - almost 'beach to boardroom' except perhaps that I wouldn't dive with it, despite its dept rating claims (an issue commonplace in the watch industry).
I just own the 1 TAG, but could well be persuaded to own another. I think this aquaracer for example is a very attractive piece, as is this calibre 5.
My only issue with TAG is their slightly ambitious MSRPs, but if you shop around you can easily get 30% off and you have a cracking watch for the money.
Heuer has a rich history in racing and chronographs, and partly because of this their vintage models are especially sought after because of their modern, wearable size (40mm or so, as opposed to most vintages of that time at a rather diminutive 34mm or so). Because of this ones in good condition sell for £2-3000 or so.
In 1985 Heuer was bought by TAG Holdings - an aviation, motorsports and hospitality company, hence the new name. In 1999 TAG Heuer was bought by LVMH who also own Zenith, Bulgari, Hublot, and various fashion and alcohol companies such as Dior and Dom Perignon.
Today the company has an incredible research and development division - check out their Mikrotimer 'The worlds first mechanical timepiece to measure and display the 1/1000th of a second', the Mikrotourbillions, and belt-driven Monaco v4.