Hey Tomdom
Fingers crossed I'll be in your position someday in the not so distant future
I'm an Artist/Graphic Designer/Cartoonist and deal an awful lot with presentation and marketing ploys etc and every so often I have the job of creating business cards/posters and things like that (although my main trade is greeting cards of the stickmen nature ;D) I have *THE* stupidly biggest collection of business cards though! It's awesome!
A few things I would make sure you do when sorting out business cards:
1. DO NOT skimp!!! PLease please please do not go to Vista Print and get 500 "free" prints! Yes yes, they're "free" (you have to pay delivery which is around a fiver)... but they do look cheap! I guess if you haven't really had many business cards to play with before you mightn't see this but really... the card quality, print quality and size is just.. not ideal!
2. Listen to what your Graphic Designer said

Less generally is more. I would focus on what you've said so far - because I'm a relative noob to the magic industry I would take on the advice above about what to put for your title as I'm not really sure what's a good plan (as in magician/close up/etc), but the other details you've suggested so far sounds good (Name, Mobby, potentially landline - your choice really, Email). Do you have a webby? If so, plonk that on too
3. Layout. Really really focus on your layout. Less is more but it completely fails if it's not punchy! If you find a print company who can do you some cards - speak to them too. They'll generally mock up an idea for you for free and they deal with this kind of stuff day in and day out
4. Photos.... be reallly REALLY careful with photos! Personally I think they're a bit cheesey, but can fully understand why they'd be used on magicians cards (easier to remember the name/face) and would probably say it's a good plan. Some people put the most atrocious pictures on business cards though and it's just not good at all! It makes me cringe! If you're going to do it, make sure it's a simple, clean cut, uncluttered photo (preferably not many colours... unless you're going for kiddywinkle parties and things... but you sound like you'd be more interested on the oldies?)
5. Colour scheme. Don't go mad! Pick a couple of bold colours and stick with them (once again - this is in the view of your target audience being adults

)
I could go on and on actually!! People sometimes do not think about business cards as being a complex thing and just bash something together.... but they're so so so important!! If they're smart and eye catching and decent quality, people won't throw them away and they will remember them! I spent.. about £40 on getting about 500ish done (full colour front and back) but that was going through a printer friend I know... I reckon I would have paid an additional tenner on top if I didn't have an acquaintance in the business
Invest in it though! For you, I'd suggest 500-1000 as you will be handing out loads to groups of people where ever you go and will get through them in no time. I reckon start with 500
If you want me to have a play about for you I will happily do so! (As in, in a friendly-way not a charge-you way!) I probably canny do so this week though as I have an exam on Tuesday (accounting... how fun!) and then am off playing with balloons and close up the rest of this week... but I could do next week? Depends on how desperate you are

I could probably direct you to *the* best printers for business cards in the world and wangle a good quote for you too!
Fleamail me if you're interested!
csouthern@akettleoffish.co.uk
If not... once again I cannot emphasise... DO NOT SKIMP! PLease please please please with cheese and chocolate and and beer and all things nice! ;D
Pheebs!