Idid a bad thing and dual classed about half way through the game and now deeply regret doing so. As a result i intend to restart the game. What i would like to know is, exactly what is the point of having a romantic encounter and who is the best to have one with

there´s no real ´point´ of a romance in terms of game statistics - you might get a minor trinket or other, but mostly it´s for atmosphere (and the romances are quite good in my opinion... especially anomen and jaheira)

as for dual classing, unless you plan to continue with tob it´s often advisable to dual quite early in the game if at all (usually at lvl 8 or 9).

As for romances, it's something to do while you get to spellhold. In my opinion, chapter 2 takes you out of the storyline, your best friend was just kidnapped and here you are dealing with an unruly druid, hunting down some cult, or clearing some trolls out of some brats keep. Granted they rationalize it being that you're scraping up money to get info from Gaylen Bayle (sp?), but still, it doesn't fit in with the storyline. What the romances I do is kinda keep you in the flow of a plot while you're out doing some assorted quests.

***No post-chapter 1 spoilers in this post***

Especially if the romance involved is with Jaheira, because it brings along all the background from BG1. After all, she's lost her husband, and you one of your best friends. It's an old, tired, hackneyed, yet *very true* plot device, that this kind of situation tends to bring women and men together.

Certainly you have to scrape up Gaelan Bayle's cash, and even more importantly, you have to re-equip yourself and a team sufficiently to try to survive the experience of going after Imoen, and by extension, Irenicus. So you have both a necessary digression, and the tension of "just when do I think we're ready to take on these heavyweights on their home turf" to deal with, and the romances are a definite aid to keeping focused on the real world of fantasy, where your characters are living people, with personalities and issues that transcend the immediate situation.