Adding to the above Comparison:

My previous Blackberry work phones have been Blackberry 7290, Pearl 8100, & the Curve 8230 so I'm very familiar with the line & found them invaluable especially the qwerty. I chose the Nokia e71 for personal/work use. I had to make the decision of whether to upgrade to a Blackberry Bold or the Nokia e71.
Previous Blackberrys vs upgrade to Nokia e71 vs upgrade to Blackberry Bold
Internet
Nokia e71 is faster than the BB 8230 & Pearl, as its 3g but apparently the BB Bold matches its speed. The BB 8230 & 8900 are slower as theyre not 3g.
You can use your home wireless broadband, or any wlan you have access to to connect to the internet, you dont have to use your phone network provider internet add on. You are given a choice of how you want to connect to the internet. This saves u using up your fair usage internet (usually 1gb p month). This is great 4 people who know where the free wireless spots are even if u dont have an add on. I use the wireless lan connection option to download videos & applications when i'm at home (or u can download to pc & use the usb cable). Wireless lan is also useful where theres no reception for your phone network provider but wlan is available to you
You can use skype, twitter etc on Noia e71. skype is usually restricted on BB's. Messenger works well on Nokia e71. I havent been able to try it on my work BB as the settings are restricted to the employers secure network.
Push Email & Attachments
The Nokia does this as well as the BB's even using the built in free Nokia e71 software. You dont need a BB enterprise a/c to do this. I just used my outlook settings , with imap as the setting (u can also have pop settings). It works fine , I can download & view, pics, adobe acrobat, & word/text docs.
Heres where the Nokia E71 is better. The built in free software has a mini office type suite & adobe reader, this means
u can download & read these types of attachments , excel, doc, txt, pdf , zip etc from a downloaded email AND from the Nokia web browser. I could not download pdf's etc from i.e a google search on BB's I've owned.
AND On the Nokia e71 u can edit & write, word type docs, spreadsheets etc & upload them to email. The Pearl & BB 8230 could not do this. You couldnt save pdfs , word docs etc from emails & then view the docs later on the Blackberry's , I don't know if they have added this feature to the Blackberry Bold . But its free on the e71.
You can set up multiple push or normal email accounts on the e71, I have 5 different emails set up on it now including a built in widows live.
1. Cost
Theres no point buying an older model of Blackberry, unless your getting a heavy discount. The Nokia e71 has more features than the earlier blackberrys for the same or cheaper price than the older models.
The Nokia e71 has all the features of the blackberry bold but its sold cheaper whether on contract or pay as you go. Both the BB's & e71 easily held by 1,000 contact addresses, & they all have removable batteries & removable microsd memory cards
Music Player
The older blackberry curve/pearl, both have decent music players/video, however I have always found that the inside headset socket always wore out with a couple of months if you use it daily for music:flamemad:. The 8230 blackberry curve has a normal stereo headphone socket so you can stick a normal headphones in without a small adapter. The Nokia headphones in the box, are poor for music. But, with a