well, warriors tend to be stronger than magi at lower levels. This gives you a bit of extra survivability to explore the basic areas, and get to learn where to find the equipment you will need when you die.

assassins are good defensively with the exception of a couple of weapons that they don't know how to use. The main strength of an assassin is stealth though. When you hide, only a limited number of other characters can see you. Also, you can see invisible people and hidden people.

Similarly with thieves. Their hide is better in civilised regions than an assassins, but worse in the wilds.

ranger is best hider in the wilds and has useful healing skills plus a powerful ambush attack.

anti-paladin is actually one I would not recommend for someone new. They can deal decent damage if dressed right, but their defenses are poor and they are not stealthy, plus people inherently distrust them.

Shapeshifter is different to the others. It is relatively weak until higher levels. However, it has two big advantages. 1. You don't need equipment in order to fight offensively. You only need it if you are being attacked. So if you die and lose everything, you can still go out and gain levels. 2. You are very powerful at high level, and don't have many tactics to decide between. Some higher level shifter forms are very good for exploring, and most are decent at fighting.

Bard is something that groups like to have with them. Personally I found bards a little fragile, but that's probably because I played an evil bard and got jumped by a group of three thieves. However, it would have been nice to actually survive long enough to have the first round of combat, which unfortunately I didn't.

Bard is a good all round character, but takes a little more skill than the others to be played at a basic level, imho.

Personally I recommend assassin to new players. Arial assassin is a decent race because it defends well against melee, but any assassin race except elf or drow is probably fine for a beginner.