Adapting toolic's approach above:

c:\@Work\Perl\monks>perl -wMstrict -le
"my $line = '2011-01-01 15:34:554 some words and numbers then email@ho
+st.com';
 printf qq{date '%s' time '%s' email '%s' \n}, (split /\s+/, $line)[0,
+ 1, -1];
"
date '2011-01-01' time '15:34:554' email 'email@host.com'
[download]

But why do you care that it's on one line and/or without a for-loop?

Update: Or, if you want to go the regex route:

c:\@Work\Perl\monks>perl -wMstrict -le
"my $rx_d = qr{ \d{4} - \d\d - \d\d }xms;
 my $rx_t = qr{ \d\d  : \d\d : \d\d }xms;
 my $rx_e = qr{ \S+ }xms;
 ;;
 my $line = qq{2011-01-01 15:34:55 blah blah yada email\@host.com\n};
 print qq{[$line]};
 printf qq{d '%s'  t '%s'  e '%s' \n}, $line =~ m{ \A ($rx_d) \s+ ($rx
+_t) .*? ($rx_e) \s* \z }xms;
"
[2011-01-01 15:34:55 blah blah yada email@host.com
]
d '2011-01-01'  t '15:34:55'  e 'email@host.com'
[download]

I suppose the definitions of all the  qr// regex objects make this more than one line, but that's life. Also, I hope you can come up with a better e-mail address regex than mine.