i don't think anyone can stop her even if she plays badly because she always finds a way to win.
but there are quite a few players that have the game to challenge her at least for one set (although i'm not expecting them to)
schett - always a threat but she's been in a slump for at least a year and i'm starting to think she won't get back to the top but if she is playing well one of the seets could be tight.
casanova - young so she haas no fear if that is possible against someone liie serena. she has beaten henin once and given her a few tough matches but she is really inconsistent and doesn't usually perform that well against the top players. she could surprise serena in one set but i don't think serena will be phased.
dokic - if she has lost weight (i don't think she has) then she would have lost some power on her groundies and you need all the power you can get for serena. jelena did give serena a tough first set at the champs last year 7-6 in the first but fell apart in the second plus she is not playing to well at the moment and is probably still a bit rusty but she is always an outside chance. she has been working with a coach and maybe they are training solely to beat the williams sisters but well have to wait a see on this one.
stevenson - has a powerfull game but can easily break down. if her serve is really on she could take at least one set to a tiebreak but don't expect her to but a score of 6-4 for in one of the sets is likely if her serve is on.
daniilidou showed at the oz open that she is good but her serve is a liability. if she has worked on that serve then she'll be a threat maybe even to take the match but i don't think she has got the serve so i'd say two fairly tight sets something like 6-4 6-3.
mauresmo - can't beat her soley from the back of the court or from the net but a combination of both may confuse serena for a set but mauresmo might be rusty.
dementieva - if she plays at her best she can cause a tight two setter and maybe even bring it to 3 sets but don't expect it.
matevzic - has the powerful game and that is all if her serve holds up it might be a tight match but it shouldn't go into three sets although anything is possible especially if serena is playing badly.
hantuchova - at AO 2002 gave venus a three set match but one round further in 2003 it only went two sets. if she is in the mood she might bring a fight to serena but rarely is she in the mood against the top players.
Go the aussies! stosur!!!
and good luck russians: dementieva, safina, kirilenko, sharapova, kuznetsova, bovina, zvonareva, dushevina.
also good luck to: azarenka, lucic, sprem, vakulenko, vaidisova, safarova, ivanovic, groenefeld, mirza, krajicek, kvitkova, larcher de brito, lisicki.