So, perhaps, Ryan, you should start a poll "What should I get next?"
As for me, I would recommend that you decide upon a theme for your models. I see you've got two Hornby post-privatisation diesels- so, the present day would be sensible. Next, you need a region- I would suggest South East England, since you have a South Eastern allocated Class 09 (they were built for the South East anyway!), and Class 60s regularly appear in places such as Hither Green (In South-East London). Passenger services could be covered by the Hornby "Class 466" multiple unit. Also, SE England is easier to get to from Holland than most other parts with lots of available models- ferry to Harwich, train to London, train to anywhere in Kent/Sussex.
So with a (Suggested) South Eastern theme, you next need to decide what sort of things you'd like to acquire. Do you just want a collection? Do you want a layout? Is your collection/layout going to be centred around freight locos and stock, or passenger services, or both?
If you just want a simple project for a first British outline layout (if you want a layout), I would recommend a South-East England TMD with a single platform passenger station. The advantages of a TMD would be that you can have lots of big engines, no need to worry about the stock they haul, lots of room for detail et cetera!
Now, according to exchange rates at the moment, you'll get £155 for your 230 Eurosof birthday money, so what I think would be worthwhile for you to do would be either buy a Bachmann 66 or a Hornby 466, and use the money left over to buy scenic stuff (or buy/save up for more locos). In fact, you could get both, although this would lessen the amount you have to spend on scenics and other stuff. Or, you could buy a 66+ Hornby Class 31+ Scenics, or 466+31+Sceics. The new 31 in Fragonset livery is very fetching! (see www.ehattons.com or www.railssheffield.co.uk for more!).