@Chris - Tread carefully- one loco as a childhood birthday present can easily lead to this:
Not just trains, but planes, trams and buses too!
Overhead shot.
As for the question of best British brand, Bachmann and Hornby are definitely your best bets, but if buying second hand, you may want to look at other manufactures too. Here are some detail shots of the collection below:
Dapol SDJR 2P No.45 - A superb model, with fine detailing and excellent running qualities; and it's 20 years old now! You can get these fairly cheaply (Mine cost £35, roughly $45-50)
Hornby D49 - Nice model, with good detailing. Running quality is fairly decent too. I got this for free (it was donated by a neighbour) along with a J94 and an N2.
Mainline Stanier "Jubilee" - Bit of a geriatric in model terms, now getting on 40! Still runs and is an excellent model though, it hasn't really dated except for the bright silver detailing on the wheels and the odd-looking BR crest on the tender.
New Hornby GWR "Castle" Class No.5028 "Llantilio Castle" - Brand new (I bought it on Friday!), this locos runs as well as it looks. Again, a superb model, and only cost me £61 (Around $80-85)
Hornby GNR J13 - Lovely model of a lovely prototype. I've got two of these, one in GNR Green and one in BR Black. I prefer the green one, not least for the fact the real thing worked around 30 miles from me in York station and is today preserved in the city's National Railway Museum.
And here's the resident diesel railcar, a Lima Class 121 converted in to a Class 122. Who else knows the difference between the two?