What Basic Equipment Do I Need for Semi-professional Photos?

If your camera will accept ehm I'd suggest you get a few extra lenses. The standard lens with most SLRs is 50mm focal length and gives a view similar to what the eye would see, but if you are serious about it you'll likely want a telephoto lens to enable you to 'zoom in' on things far away and fill the frame with them and a wide-angle for when you can't get far enough back to get the whole scene in. With practice you can use them for some really good creative effects too, deliberately introducing distortions that kind of thing. A couple of filters might be a good idea too. But, there are a lot of things you can improvise with to get some great effects. e.g. for portrait photography, try shooting through a silk scarf or a stocking for a lovely soft-focus effect.

I'm not really sure what you mean by semi-professional. If you are a serious photographer and want to sell your images to magazines I suggest you buy a DSLR with the highest resolution you can afford. I would invest in good glass optics and learn how to use the camera's full potential. Add a good flash (it is amazing how much they want for these units now) or two with an off-camera synch-cord. A solid tripod is helpful. You can play with longer exposures and larger f/stops that can make dull situations more interesting. You might also invest in a polarize and some graduated neutral density filters (Cokin makes several sizes and colors.....I would stick with gray or tobacco) And an alarm clock....some of the best situations and light occur early in the morning (or late in the afternoon) when the light isn't so harsh.

You don't need a lot to make good photos...you DO have to think about what you want and how you're going to get it.

A decent camera, Film is best quality but a good Digital SLR will work too

I recomend a good sturdy tripod as well.

Use the light around you wisely

Radio triggers to fire those speedlights off camera (I use RF602's - about £20 a set) plus a couple of lightstands and modifiers (softbox or umbrella - set you back about £30-£40)