You said you have a team that needs a lot of rebuilding help.

Going for a young pitcher who has performed well for less than a season is a big gamble but position players who excel and are touted rarely disappoint (Beltre excepted). High calibre SS's are very valuable and Reyes looks like the real deal. You can't afford to pass up an almost certain star for the shining star pitcher of the moment.

That young pitcher could have arm trouble any time (Bud Smith) or have one strong half season (Simontachi). If you had a strong team, I'd say gamble on the pitcher; but you have lots of time to pick young prospects in the later rounds and hope they turn into stars in 2-3 years. Build a solid starting lineup with lots of young pitching prospects saving the ones that pan out rather than pinning all your hopes on the next Rick Ankiel.