A fairly good guide is to look at the FHM top 100 and choose from there it's the best selling mag in the UK i think and seems to get the best girls.
This is the 2005 full list, in red are celebs i know of and blue are others who seem to be a bit famous.
1. Kelly Brook
2. Cheryl Tweedy
3. Angelina Jolie
4. Michelle Ryan
5. Elisha Cuthbert
6. Britney Spears
7. Abi Titmuss
8. Sarah Harding
9. Beyonce Knowles
10.
Charlotte Church
11. Eva Longoria
12. Jennifer Love Hewitt
13. Rachel Stevens
14. Lindsay Lohan
15. Carmen Electra
16. Lucy Pinder
17. Jennifer Ellison
18. Keira Knightley
19. Alyssa Milano
20. Christina Aguilera
21. Louise Redknapp
22. Jennifer Lopez
23. Paris Hilton
24. Kirsty Gallagher
25. Katie Holmes
26. Natalie Pike
27. Halle Berry
28. Tina O'Brien
29. Victoria Silvstedt
30. Jessica Simpson
31. Jennifer Garner
32. Michelle Marsh
33. Joss Stone
34. Tera Patrick
35. Nadine Coyle
36. Maria Sharapova
37. Kylie Minogue
38. Nikki Sanderson
39. Delta Goodrem
40. Anna Kournikova
41. Tanya Robinson
42. Holly Valance
43. Kristin Kreuk
44. Kimberley Walsh
45. Charlotte Marshall
46. The Olsen Twins
47. Denise Richards
48. Kirsten Dunst
49. Jordan
50. Pamela Anderson
51. Sarah Michelle Gellar
52. Heidi Klum
53. Cameron Diaz
54. Monica Bellucci
55. Christina Milian
56. Kayleigh Pearson
57. Jessica Alba
58. Mariah Carey
59. Sienna Miller
60. Eva Mendes
61. Billie Piper
62. Fearne Cotton
63. Teri Hatcher
64. Mischa Barton
65. Jodi Albert
66. Lisa Snowdon
67. Cat Deeley
68. Scarlett Johansson
69. Laila Rouass
70. Leanne Wilson
71. Holly Willoughby
72. Liv Tyler
73. Natalie Portman
74. Sophie Howard
75. Jenna Jameson
76. Lucy Liu
77. Nicola Roberts
78. Jennifer Aniston
79. Rebecca Romijn-Stamos
80. Estella Warren
81. Anastasia
82. Tara Reid
83. Eliza Dushku
84. Danni Minogue
85. Kate Beckinsale
86. Dido
87. Brooke Burke
88. Jamie-Lynn DiScala
89. Jamelia
90. Shannon Elizabeth
91. Frankee
92. Jill Halfpenny
93. Fergie
94. Tiffani Thiessen
95. Hilary Duff
96. Nicole Kidman
97. Salma Hayek
98. Avril Lavigne
99. Rachel Bilson
100. Catherine Bell
Take this link and it will give you the list with a yahoo images linky thing.
http://uk.news.yahoo.com/hot/office-attachments/girls05.html
Anyone from Hollyoaks (teen/early 20's soap) is usually a bit of a looker
You could try here for more...
http://britsite.com/forum/
Other than that the minogues are possibly Honourary Brits and the papers seem to love Big Brother contestants for years after they become unfamous. Hope this helps.