Pro's
*fantastic damage
*usually targeted last in team fights because of undying rage
*lots of mobility(ex : jumping over several walls with flash and spinning slash)
*not as squishy when building full damage compared to other champs
*good lane sustain because of blood lust, combined with life steal
Con's
*you will be seen as a major threat and will be watched
*almost every player knows what tryndamere is capable of, and try to counter it. (ex: when you are being ganked if the enemy is smart enough, someone will wait in a brush near where you would be able to wall jump to safety, sealing your death)

Recomended
*heal- helps alot in team fights, and those tough opponets 1vs1, it can be a very fight changing spell if used properly
*flash- more wall jumps
*ignite - always devastating

Others
*exhaust - if you have trouble catching up to opponets
*clairvoyance - if you dont have a stealth/ skill warding ally (ex: teemo, evlyn, twitch, caitlyn)
*ghost - if you prefer other than flash

Never
clarity - YOU DONT HAVE MANA. Sadly enough iv'e seen manaless champs with it, want to make it clear. =^)

Over all Tryndamere is one of the best starting champs, easy to learn, and a lot of fun. Don't forget to jump over them walls!!!!