RE: skills
Well, it all depends on what sort of game you want to play... Unlike many computer RPGs, in the Fallout games those choices actually are rather important, and they're real choices too - you cannot choose the 'wrong' skills so that you cannot complete the game as a consequence, although you can make it a good deal more difficult for yourself. And there are some options that are available only to characters with certain percentages in certain skills in some parts of the game.
Speech is important because it and your character's Intelligence determine the choices you'll get during conversations with other characters in the game.
The way I always play it is to tag Speech, Lockpick, and Energy Weapon. Yes, that means I never tag Small Arms and I never spend any points on it because I can improve it with the Guns and Ammo magazines. In Fallout 2 those are more rare, though.
I'd say improve only on Speech until it reaches at least 80% or so, then improve on Lockpick a bit more than Speech until both are at least 100% - that'll give you the most options and get you through a lot of doors.
I always tag Energy Weapons because I like them, but the early parts of the game certainly are more difficult as a result!
If you don't want to spend points on Science or First Aid or even Repair then you can just rest in Vault City and buy the relevant books over and over as they seem to replenish about every four days or so. Make sure you're a citizen first, though, or it'll cost you too much. You'll also need gear or money to trade for these.
Still, once Lockpick and Speech both reach 100%, I'd get Doctor to about 90% since that's very helpful from Vault City onwards.
A high science, at least 80%, is helpful in some cases once you reach New Reno.